Fixing the Fridge, Again!

The fridge broke again.  Sigh.

As I've mentioned before, this is a Norcold Gas Absorption Refrigerator model 6162.  It works by heating a loop of ammonia - pressurized so it is liquid at steady state but transforms to a gas when heat is added.  Our fridge is a 2-way, which means the heat comes in the form of either AC heating element or an LP gas flame.  (3-way versions are slightly more expensive and feature a DC powered heater, typically hooked up to the chassis battery.  This is nice because it means you don't need to run the generator or use LP gas, but it quickly drains the battery.)

Over the past several days while we've been dry camping at The Grand Canyon, we've had to run the fridge off of LP gas.  This is a change from all the other places we've been - the fridge has run well on AC power.  However, after just a day, the fridge failed and we had to quickly either eat the food in the fridge or put it into our backup cooler we'd brought along just in case.

Here's where I got myself into trouble.  The panel to access the fridge guts is easily accessible on the outside of the RV.  There are some aluminum tubing LP lines connecting the main LP gas source to the burner.  Thinking that they were clogged or kinked (which they were) I started to disassemble the lines.  The aluminum was so old and corroded to the brass fittings that instead of coming apart cleanly, the parts folded, bent, and twisted off.  It was a complete mess, and in the end I wound up with a bunch of valves and a whole mess of broken LP lines.  To make matters even worse, based on some previous calls to customer support, I knew I could no longer easily get parts for the fridge, especially on the road.

 

Link to the annotated picture of these parts...

We stopped in Kingman, AZ on the way to Las Vegas and I purchased some parts and tools to try and rebuild the fridge LP system.  The goal was to recreate the aluminum tubing using copper tubing I'd found at Home Depot used for ice maker hookups.  It was a little tricky because the bends were aggressive, nearing the minimum bend diameter of the tubing used.  Additionally, the ends needed to be flared - to fit into a flare fitting.  I'd never done any of these operations, so I made sure I had extra tubing to play with.

Making new tubing parts

After a couple of trials, I was able to rebuild the necessary LP system tubing completely.  Using a toothbrush and some soapy water I checked for leaks and then fired it up. 

Checking for leaks

The size of the flame in the LP chamber seems to indicate that the fridge should work much better now!

Getting the oil changed

Getting the oil changed in your car is easy.  Ever tried it with a full-size Winnebago?  Hint - it involves both you and the manager on the phone getting dimensions of the bay doors and the Winnebago to see if it fits!

We had plenty of height to spare, but we were within half a foot on each side of it fitting width-wise!

Simon in his natural environment

The very first thing I saw was green shoelaces.

Seeing Simon in Albuquerque was a really great time.  He was wearing all dark clothes including a dark hat, and hadn't shaved in weeks if not longer.  Very dark.  Except his shoelaces.  Wow.  You could see those suckers coming a mile away.  Apparently there was a long story and these weren't the originals that came with the shoes, but it was really colorful in any event.

The first order of business was seeing Simon in his natural environment.  His loft apartment overlooked downtown Albuquerque and was really amazing.  He made use of his large glass windows to brainstorm ideas and shopping lists for his projects.

We asked Simon to take us to some of his familiar haunts - so we ate breakfast at a Flying Star both days.  This was hands-down one of the best breakfast places I've ever eaten at.  Their desserts were fabulous - I had carrot cake and a raspberry chocolate cake that was amazing and had to share it with both Simon and Sarah.

That afternoon, we walked up the street to the UNM ARTS lab Simon occasionally worked at, and met some of his colleagues.  They made some really good use of a CNC machine to cut wooden parts out and make a projector dome for visual exhibits.  I also got to see some of their past creations - some work with Wii sensors and balance boards to build video games using the domes.  It was really amazing.

For dinner, I suggested we cook Simon a traditional RV supper.  It was a hit - we had chicken and Spanish rice, with a nice salad and some frozen vegetables, along with some mashed potatoes.  After dinner, Sarah collapsed to the rear of the RV to go to sleep while Simon and I stayed up until 4AM playing Ticket To Ride with the 1910 Expansion.  (I personally don't think you can really play the game without the expansion - after a few games it becomes pretty obvious where your opponent is going and the game loses its fun factor)

Breakfast the next morning was more of a "breakfast food for late lunch" since Simon had decided to shave his beard.  I think he was motivated by our visit to get out and do some things he'd been putting off for a while, including shaving.

We were a little sad to leave Albuquerque.

Laundry in the RV

Sarah finds a new place to dry her shirts

Plumbing and Door Fixing in Las Cruces

Busted!

Sarah broke the door.  We were using the screen door only since it was so nice outside (72 degrees, slight wind, no humidity) and she pulled on part of the screen door that was a metal panel in a couple of frame slots.  The metal panel came out a little bit.  To her credit, she managed to halfway fix it before calling me in to complete the repair, but still, another repair to be made.

Hand-tightening fixtures

Later in the day, I had a plumbing issue to finish up.  Early in the trip I found the bathroom sink leaking a little bit from the pipes connecting to the faucet.  This wasn't the first time I'd seen this - on our trip to Alexander Springs, I found the shower faucet leaking into the wall.  The problem this time is that the RV is old, and the connectors used aren't really made to deal well with rattling and shaking over the open road, over years and years of use.  They're hand-tighten nylon connectors that mate up to nylon fixtures.  Over time they've come loose, and started to leak.  In the case of the shower, a little bit of teflon tape seemed to do the trick.  The faucet in the bathroom sink could only be attacked from below, and was really painful to get at.  I was happy to have the job done.

Not comfortable.

Fixing the Fridge

PC Fridge Fan

Our fridge has been acting up.  It's just not keeping up.  The freezer is great - everything stays frozen and there are ice crystals on the walls.  The fridge has a metal radiator which gets cold and occasionally has ice on it, but nothing in there seems to stay cold, getting up to nearly 50 degrees at times.  (It should be around 30-40 degrees)

After having to throw away food for the second time, it was time to do something.  I stopped at a local Radio Shack and purchased a 12V car cigarette lighter and a PC case fan.  Since I had no soldering iron (didn't make the cut for the road tool box) I used nylon zip ties and flaming duct tape.  My theory is that the radiator is cold, but there's not enough air circulating in the fridge to take advantage of this.  If I can force air over the radiator I think it may work better.


When I woke up this morning, the fridge was 33 degrees.  I think it just may be working!

A change in plans

The bad coffee pot

This day was well planned and had tons of potential.  The mission:  Get to Davis Mountains State Park, where we'd stay for a couple of days and explore the nearby historical sites and mountain hiking trails.

The day started with coffee.  Seems like a small thing, but we were on our second coffee maker.  To be sure, I hadn't spent a lot of money on the coffee maker.  (You can buy one for yourself for 20 bucks.  I liked it because it was small (fit into a cabinet) and used a cone filter, which I'm partial to.  It also had a timer, which I wanted so we could have it turn on for early morning hikes later in the trip.  Unfortunately, the first one I bought correctly brewed a pot of water during the initial cleaning cycle and then set off the carbon monoxide detector when burning-rubber smelling smoke came out of the back of it, seemingly from the hotplate contacting some wiring inside the coffee maker.  I turned it in to get a second pot which so far has worked well.  I just hope to get $20 worth of coffee use from it.  That's not asking much, right?  In any case, we had coffee.  Check.

Our spot at The Alamo KOA

This was going to be a long drive.  In the past we'd decided that at most we wanted to drive 3-4 hours at a time.  More than that was really tough on the RV driver (me) since cross-winds and semi-trucks caused a lot of stress.  Unfortunately, 3-4 hours didn't get us where we wanted to go that day, so we decided to make a run for a state park 430 miles away - Davis Mountains State Park.  We left the Alamo KOA in San Antonio around 7:30 in the morning, getting gas on the way out of town.  This was pretty good time we were making to tear down camp and get a fuel fill, compared to previous days.  We were really getting the hang of it now.


I felt good, there was no wind, and since it was Saturday, there were very few trucks and very little traffic.  It was a gorgeous day and we ran with the windows open and satellite radio blaring most of the way.  We made a few stops to make lunch and stretch our legs.  We made really good time despite the winds slowly building throughout the day.

Which direction to 307?

Can we go now?  Can we?  Can we?  Please?

Finally, we got off the interstate and jumped onto a 2-lane highway that would take us the rest of the way to the park.  It was long and straight, and we got abused by cross-winds.  We stopped a few times to rest and take some pictures.

Just about 20 miles from the park we spotted a wildfire in the distance.  As we got closer, it became clear that this was a very large fire.  It was still off in the distance, and I'm sure it was being taken care of.  We resumed talks about visiting the nearby McDonald Observatory where there was a large star party that night - sounded pretty cool and she hadn't ever done that kind of thing.



As we neared the town of Fort Davis, TX, the fire got larger and the smoke became more menacing.  This was the last town before the state park, and we elected to make a beeline for the park before the fire got any closer.

We checked into the park with very little fanfare.  A very nice park, and we were looking forward to some of the local activities like hiking and the historical monuments.  Unfortunately, as we started to unpack, the ranger came by and said "be ready to evacuate."  Really?

Now I'm concerned.  While we had a full tank of gas (nearly 40 gallons in the tank, plus a couple of extra tanks I'd brought along just in case) we didn't really have a place to stay for the night if we had to evacuate.

Within an hour, the local sheriff came screaming through the campground on the loudspeaker saying "LEAVE NOW.  US-118 NORTH.  LEAVE NOW."  Holy cow.  Time to move.

One nice thing about the RV we've got is that it's pretty simple.  All the new RVs have electrical slideouts and automatic awnings and leveling devices etc etc.  Ours?  Nope.  We gots wood blocks to level it with.  A manual awning (which we typically leave tucked away).  No slideouts here.  When the order came, we unplugged the RV from the electrical outlet, started the engine, and left.  We were likely the first ones out of the park, leaving within 3 minutes of getting the official order to go.  Good thing too, as we later discovered that the winds (which had been gusting to 50mph near the park) had shifted, and as the last campers left the park the flames were just coming over the ridges overlooking the park.  A little close for comfort.

With no place to go and no plans anymore (we'd planned to stay at that park for 3 days) we decided to go check out the star party, which was conveniently along the evacuation route.  The road went from 5,000 feet in elevation to nearly 8,000 feet in elevation.  Our little RV powered by a Chevy 454 thundered up the hills, proving surprisingly spry in the corners despite being a literal house on wheels.  All the work on the engine and suspension I'd done in the previous months just paid off.  I had some concerns in the back of my head - with the fire moving at nearly 10mph, if the RV broke down, we'd have to abandon everything we own to be consumed by the fire, fleeing with just the clothes on our backs in the back of a sheriff car or something like that.  There's just no way to outrun a fire like that.

Letting the engine cool off

We arrived at the top of the mountain.  The engine was running a bit hot and I didn't want to push it too much further, so we found a nice spot in the parking lot to let it rest while we checked out the star party. 

Imagine our disappointment when we learned that the fire had knocked out the power to observatory, and the star party was canceled.

Refugees fill the parking lot

The observatory quickly filled with refugees from both the campgrounds and the nearby town of Fort Davis, which we'd driven through on our way in.  Apparently several of the houses fell victim to the wildfire and were consumed before firefighters could get to them.

At 7:00 it was time to find a new place to stay for the night.  We took off down the road, only to encounter very steep grades and twisty windy roads.  I was thankful for the newly rebuilt brakes - the descent was very tricky and engine braking didn't cut it on some slopes.

The final few miles down the mountain were visually stunning.  The wildfires produced a hazy red sunset and some gorgeous views of the area.

We were able to find a place another 90 minutes from the bottom of the mountain where we could park the RV for the night - a KOA in Van Horn, TX.  All told, we'd driven more than 520 miles in a day.  Our typical average is 40-50 miles an hour (which accounts for gas stops and rest breaks) which put me at nearly 10-12 hours behind the wheel by the time we pulled into the KOA in Van Horn.  I had a beer, a shower in the RV, and collapsed on the bed. 


It was the best night's sleep I've gotten in a long time.

Tink Tink Tink Tink

One of the things I enjoy is listening to cars and trying to figure out what's wrong with them by the noises they make.  Often times, you can pretty easily recognize belts slipping (and sometimes which belts) or dead CV joints, bad suspensions, broken exhaust manifolds, etc.

When the RV started making a noise about halfway between Baton Rouge and Baytown, I was concerned.  Really concerned.  The noise appeared to start at about 10mph and stopped at about 45mpg (or the wind noise drowned it out).  It sounded like it was coming from the front left wheel, which was super concerning since I'd just had the front wheel bearings completely replaced and now I was nearly a thousand miles from the place that did the work.  I don't have the tools or skills to fix this, so we'd be talking an expensive tow and then getting the right parts in, all while trying to find a place to stay while our house on wheels got fixed.  The noise was definitely speed related (not engine related) because I could feather the throttle and didn't hear the noise change frequency.

Leaving Baytown, I'd had enough.  I wasn't sure what the noise was, but I wanted more information.  I pulled off the road and had Sarah jump in the driver's seat.  My intention was to pull the wheel cover off and listen to the noise - "TINK TINK TINK" and see if I could determine if it was coming from the bearing, the brakes, or something else entirely, possibly something caught up in the wheel.

When I pulled the wheel cover off, the problem was obvious.  One of the lead weights had come loose from the rim and was sliding back and forth on the rim, hitting the wheel cover and rim alternately.  This accounted for the noise and once I removed the weight, the noise was gone.

What a relief.

Evil Lead Wheel Balancing Weight

Have I earned my RV repair patch yet?

I can't sleep - pretty wound from yesterday and just wanting to get on the road.  Sarah is struggling with the long adventure of packing and getting ready, and I can completely understand.  Yesterday we worked on trying to get on the road from 2PM until 9PM, and we still have hours and hours to go.

The problem is that the RV needs love.  Lots and lots of love.  Yesterday, the generator decided to act up at the last minute (a two hour ordeal) a plumbing issue arose (the shower leaked) and there were a couple of additional little things I needed to finish.  The two surprises - the generator and the shower - cost us about 5-6 hours yesterday.  That's pretty typical at this point.

Here's the deal - we bought a used RV.  It was pretty cheap, which was one of the motivating factors - less than $10K for the RV, the tags/title/taxes, two major repairs (things beyond my skillset/tools) and a few parts.  That's pretty good considering how much a new RV can run.  We looked at new RVs and they basically started at 10x that.  Clearly not in the budget.

We did look at renting, but renting one (including the miles for a cross country trip) just didn't add up - the cost was going to be more to rent than we've spent on the RV itself.  We also suspect this is something we'll use for a while, and we want to try out.

If you're considering going down this road, I would encourage you to think very critically about your skillset and your time.  And maybe take a spin down this list of repairs I've done to get a good idea of what it might take to get a used RV running.  For a little frame of reference - I'm pretty comfortable tackling just about any house repair job, from drywall repair to roof repair to complete in-wall plumbing rebuilds or electrical issues.  I'm also pretty skilled at car repair - I can typically replace an alternator in less than an hour, I've worked on basically all major systems from electrical to mechanical (but I won't touch a transmission - that's some sort of magic I don't want to deal with).  With that in mind, here's my list of accomplishments...in rough chronological order of breakage/repair:

• Hot water heater
• The burner was burned out (would not create a flame correctly).  Repaired at the RV place prior to purchase.
• Brake lines
• As we drove it off the lot, the brakes gave way.  Had a local repair shop deal with this one since the brake pedal basically sunk all the way to the floor.  There was just no way for me to work on this since it was basically still stuck at the dealership.  Very frustrating since this place (an Orlando dealership off of Fairbanks specializing in RVs and trailers) failed to tell me the RV had NO brakes at all.  (I'd avoid this place like the plague if you can)
• Range
• The main valve controlling gas to the stovetop and oven needed to be replaced.  I'd never worked on propane fixtures before, and it reminds me a little of working on brake lines - same kind of tubing and joints.  Used soapy water to check for leaks.
• The oven burner needed some love.  I found a spider web in an unfortunate tube portion of the burner, which didn't allow the propane and air to mix and create a flame that would light a good pilot which prevented the entire system from turning on and making the oven hot.  This took FOREVER to find - I finally had to take the entire system apart for cleaning as a last resort.
• Furnace
• This device has a large propane burner which burns in a closed loop venting to the outside.  The closed loop is a large metal heat exchanger and a fan blows over this to keep the RV warm inside.
• The furnace leaked Carbon Monoxide into the RV - very dangerous.  I only discovered this while I was working on the RV with the furnace on and was getting headaches, at which point I purchased a CO detector.
• The fan was pretty old and there were mud dauber nests in the entire thing.  Once I had that cleaned out, I still couldn't find a hole in the heat exchanger.
• Purchased a used unit on eBay, replaced most of the guts of the unit with the newer one.  Had to leave some of the propane tubing in since it was specially fit to the Winnebago.  
• Broke the valve responsible for turning propane on and off while I was trying to move tubing around.  Had to order another one.
• Works perfectly now.
• Installed mud-dauber guards
• These are screen meshes that go over the vents for the furnace
• They are supposed to keep mud daubers out of the appliances.  I really hope they do.  This was a super annoying problem.
• Cutting board sink plates
• The sink is recessed and had a particle board sink plate go over the top of it.  This had absorbed water over time and swelled.  It was pretty gross and old.
• I built a couple of butcher-block sink plates to go in here.  They double as cutting boards for chopping up vegetables etc.  
• They look really good and now Sarah wants a couple for every-day use.  (Her Mom got my prototype and loves it...)
• HVAC Blower Motor
• Seems to overheat and stop running after a few minutes.  Never did get this working, despite spending a TON of time working on it.
• I think it's the resistor block, but I haven't been able to replace it yet.
• Engine
• Replaced spark plugs with new ones.  The old ones were pretty beat up.  It's a 1993 Chevy 454 and I figured it was about time anyway.
• Lots of coolant hose replacements.  Basically all of the hoses were dry rotted.
• Replaced coolant loop to the hot water heater.  This RV has a neat feature where the hot water heater can be driven by hot coolant from the engine.  I don't think it works terribly well, but it's a neat idea.  Had to replace the hoses anyway.
• Fridge
• This is a really clever device.  It runs on either AC current or propane!  (Yes, propane - it burns propane in an ammonia heat exchanger loop to make the inside of the fridge/freezer cold - pretty amazing if you ask me)
• This is one of my proudest achievements.  The fridge was so old I could not get parts anymore.  I ordered something close (with the same burner type) and pieced together some tubing attachments from the small brass plumbing fixture section at Home Depot.  This fridge works like a champ now.
• Radio/Speakers
• The previous owner installed 10" kickers and some additional speakers in the RV.  Cool, but maybe would have been nice to leave the system in a working condition when you sold it, after you decided to pull the amplifier out.
• Rewired the radio, retraced the speaker wires and reconnected factory speakers.  Disconnected old amplifier wires until I pony up the $150 or so for a new amp.
• Sway Bar Bushings
• This is a large metal bar that helps to keep the RV from tilting too much in corners.  It essentially links the left and right side suspension together.
• The bushings basically didn't exist and it sounded like I was running over my toolbox every time I hit a bump.  $10 in rubber bushings and 3 hours later the RV drove MUCH better. (the bolts were tough to remove - had to get out my 1/2" drive socket wrenches and a very long breaker bar to loosen them) 
• Steering Dampener
• This is a gas shock that keeps the steering from bouncing left and right when you encounter bumps.  Replaced.
• AC Converter
• This is essentially a big "wall wart" you'd use to plug any electronic device (like your cell phone charger) into the wall.  Same deal - you plug in the RV to 110VAC and there are 12VDC appliances that need power and batteries that need charging.
• The old unit was some sort of large transformer that got really hot and was full of nasty fuzzy stuff.  I think it almost caught fire since I found a black burned section of carpet under it when I replaced it.
• Bought a new "switching power supply" (a larger version of the supply in your PC) which works like a champ and runs a lot cooler.  Installation was super easy but I wound up replacing the fuse panel while I was at it.
• DC batteries
• These are in good shape, but I added another battery to the chassis to allow me to run the furnace overnight with a little more piece of mind.  Had to get a few cables to attach the two batteries.
• AC Inverter.
• Not to be confused with the AC Converter - this connects to the chassis batteries and creates 110VAC from the 12VDC batteries when the generator isn't running or you aren't plugged into the wall.  I'll be using this for running the laptop when we're running down the road, or the TV at night.
• Major plumbing blowout
• This was exciting.  We went camping at Alexander Springs a few weeks back.  While doing dishes I heard a pop and the water pump started going crazy.  Looked outside and found that a drain in the RV had let loose and now the entire contents of our on-board water supply were spilling out.
• It turns out a small plastic plunger was forced down the line - this was used to drain the system but was not properly secured and blew out.
• Used chapstick to lubricate the o-rings, secured the plunger with the metal ring from my car keys.  Disaster averted!
• Front wheel bearing replacement, brake system overhaul, new front air suspension helpers
• I suspected we had some sort of wheel bearing issue after our trip to Alexander Springs.  There was a squeak coming from the front wheels I wasn't happy with.
• I took the RV to crawford tire in Ocoee - they are GREAT.
• Front wheel bearings were gone.  As in - not there any more since they had burned up.
• Brakes were ruined because they were old.
• Took the opportunity to put in new front air suspension helpers - basically air bags to help the suspension out when the RV is fully laden.  (They make a huge difference)
• Vacuum line replacement
• I noticed that while I could get hot air from the HVAC blower for a few minutes (see an earlier post about the blower motor resistor block overheating) but I could not get the air to come out of any vents except the defroster.
• Found a complete rupture in the vacuum line coming through the firewall.
• Replaced lines and fittings.  Can adjust where the air comes out of the ducts for the 10 minutes the blower motor runs now.
• Generator
• Changed oil.  Never seen red oil.  Carmel colored (new) and black (old) yes, but this was rust colored.  Even my wife, who has seen me change the oil maybe a couple of times at most remarked that this was unusual.  I hope it's not a sign of bad things to come.  Used high-mileage oil in the hopes that it will keep the generator running longer.  Also replaced oil filter.
• Tried to replace fuel filter/pump.  It's a special Onan part and will be tough to replace.  Also, there's a rounded off nut fitting that makes this tough.  Gonna see if I can get a new part on the road.
• Fixed the governor linkage with a couple of 2 cent washers.  This linkage keeps the generator running at the correct RPMs by varying the throttle based on load placed on the generator.  (If you turn on the A/C you'll require more juice)  The linkage was rubbing against the protective cover.  I added a few washers and it's running great now.
• Replaced back window shade.
• Purchased a $10 window shade from Ikea to replace the $8 walmart special that was dry rotting and cracking.
• New one is no longer spring loaded, deciding to spring up/down on its own schedule.
• Caulked/Painted the roof (Sarah!)
• The roof is rubber, but it's old.  Used roof paint from home depot to protect all the seams etc after we finished caulking.
• Fixed firewood compartment
• There's a compartment near the door entrance that is absolutely perfect for firewood - good size, under the awning, etc.
• Apparently the previous owners thought so too.  I know this because there were wood scraps in there.
• I also know this because the old wood scraps had termites in them at one point, which ate part of the door frame in that compartment.  Replaced the bad part of the frame with some green treated wood and some caulk, plus new screws.
• Built new shelf
• There was an old compartment above the wheel well below the closet.  Now it's just a hole.  The previous owner seemed to just add a thin piece of plywood which bent with the smallest of items placed on it.
• Rebuilt shelf to be able to take more weight.  Added side and back panels so you're not looking at bare wood and things can't fall into the depths of the RV framing.
• Installed satellite radio
• Drilled hole and caulked hole in roof for satellite radio antenna.
• Fixed in-dash radio mount.
• Radio was kind of floating/falling in the dash from the previous owner.
• Found the appropriately sized metric bolt and a few fender washers to secure the radio to the dash structure.
• Built windshield washer sprayers
• I don't understand this one.  There was a working sprayer on the vehicle but the tube ended in the engine compartment, spraying all over the radiator.  The tubes that went to the wiper arms had clearly been removed.
• Bought new tubing and makeshift nozzles (1/8" vacuum fittings) at pep boys.  Built new wiper sprayers.  Works great.
• Adjusted main door.
• The latch on the main door was loose and the door never closed quite right.  A quick adjustment to the door jam fixed this.
• Added brita water fauctet filter
• This should help with the drinking water issue - it's a three stage filter and claims to filter out all the bacteria as well as the chemical contaminants.  Fit right on to the RV faucet.
• Installed fridge thermometer.
• Since the fridge is full of perishables and isn't necessarily plugged in all the time, we need to monitor the fridge temperature to make sure it doesn't warm up and ruin everything.
• Installed thermometer with alarm.  Digital with one decimal point.  It's nice to see how cold it is and see if it's getting colder after I turn the fridge on - the fridge doesn't make any noise so it's tough to tell if it's on or not.
• Fixed shower leak
• The last few times I've powered the water pump on for any period of time, I've noticed a slow leak in the back of the RV under the wheel.  It's right under the shower stall, but outside.
• Took the shower valve off the wall (this was easier than expected, thanks Winnebago!) and discovered plastic hand-tightening fittings that had come loose.
• Some teflon tape and gorilla grip later the faucet was no longer leaking.
• Special note: I'm surprised at how well the shower works.  I've stayed at hotels where the shower was worse than this one.  I really think we should be able to take quick but good showers in the RV.  Unexpected!

I've enjoyed working on the RV, but this has been one long repair project.  I'm glad I'm almost on the road now.