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Think Like a Mechanic and Save on Repairs

| Updated Apr 9, 2019

I know many of you Roadtrek owners are feeling a bit apprehensive now that the company is no longer in business, worried about getting repairs done, but take heart. There's a surprising amount of things you can puzzle out yourself and save big bucks on repairs. Let me walk you through a problem I just had and solved by thinking like a mechanic. Which is easy for me – i AM a mechanic. But follow along and you'll see the diagnostic reasoning, which anyone can do.

Think Like a Mechanic and Save on Repairs 1
Here are the exotic tools and supplies I used to fix this problem. Total cost maybe $30. The stubby screwdriver was free 😉

Here's the problem – my 7 cubic foot Norcold compressor refrigerator started acting funny. First it ran continuously and didn't get cold, then it quit running completely the next night. I woke up to a dead refrigerator.  OK, first thing you do is the preliminary catastrophizing. These refrigerators cost $1400. Or even worse, suppose my 800 amp-hour lithium battery is going bad? I'll have to take out a second mortgage. Wait – I'm a fulltimer, I have nothing to mortgage. Woe is me.

After getting the initial panic out of the way, I start to think through things. I run an extension cord from the small inverter to the fridge plug and give it some shore power. Like Lazarus, the refrigerator starts running perfectly. OK, scratch the $1400 – this is a 12 volt power supply problem, not a deceased refrigerator. I check voltages and notice a half volt voltage drop between the reading at the lithium cells and what's coming out of the battery management system (BMS). More panic. The big relay in the BMS must be getting resistance from corroded contacts or something like that.  I email Tony, the expert who worked with Roadtrek to design the lithium batteries, who talks me down off the ledge by informing me that there are diodes in the BMS to prevent enthusiastic amateurs from wiring them up backwards and exploding them, which explains the slight voltage drop. I regretfully conclude that my lithium battery is fine.

Think Like a Mechanic and Save on Repairs 2
Oh, and you need some assorted crimp connectors and spare fuses. Another $15.

These refrigerators start running continuously and not cooling – my initial symptom – when they get low voltage, down around 12.2 volts or so. Roadtrek discovered this immediately after using them, and implemented a fix for it – pull out an inline resister in the power line. I had done that years ago, but now I was still getting the low voltage symptoms. I get out my trusty voltmeter and check the voltage at the switch I use to select which battery bank to run the refrigerator off of.  You don't have one of these switches – the point is that I can see how much voltage is going into the refrigerator. It's  fine – exactly what was coming out of the BMS, 13.2 volts. Plenty of voltage, it should run fine. I need to check further downstream. Something between the switch and the refrigerator has too much resistance.

Think Like a Mechanic and Save on Repairs 3
The inline fuse and holder. It's right on top of the refrigerator – you can't miss it.

There is an inline 15 amp fuse that Norcold put in the 12 volt power supply line right before it goes into the circuit board on top of the refrigerator, so I pull the refrigerator out. To do this, you pop off the black plastic molding on either side of the doors, remove the twelve screws holding the refrigerator flange to the cabinetry, and slide it out a foot. Easy. And there on top of the fridge is the fuse holder, with one of those old fashioned glass tube type fuses. I take the fuse out and it looks OK (the wire inside the glass tube is intact), but there's a burned spot on one end of the fuse. I clean it off and reinstall it – and the refrigerator starts running on 12 volts. My estimated repair cost plummets by three orders of magnitude.

Think Like a Mechanic and Save on Repairs 4

So I'm done, right? Not so fast. It runs, but i notice the fuse holder feels warm. Electrical resistance produces heat (ask any toaster oven) so somewhere inside the fuse holder is a bad contact. I look at the fuse holder – there's some discoloration on the left side – a white band around the fuse holder has a tan discoloration in one spot. Something got hot here. I slide the black plastic half off the wire, and the wire is toasted. The connection between the wire and the metal bead at the end that contacts the fuse had gone bad. This is a two dollar part installed by the refrigerator manufacturer, and it failed. But I don't have another one – I am sitting out on BLM land in the middle of nowhere. I need to improvise.

Think Like a Mechanic and Save on Repairs 5
Don't have a fuse holder? Make one.
Think Like a Mechanic and Save on Repairs 6
My improvised 15 amp fuse holder to replace the failed fuse holder.

I have a 15 amp fuse, but it's a blade type fuse. Out come my electrical pliers and an assortment of crimp connectors (you need to carry these, total cost is maybe $15), electrical tape and dielectic grease out of the glove box, and I splice the blade type 15 amp fuse into the line where the glass tube type fuse used to be. The female spade crimp connectors go right onto the blade type fuse. a little Gorilla Tape for strain relief by attaching the wires so if you pull on it it won't put tension on the fuse, and regular electrical tape around the crimp connectors on the fuse. Now the refrigerator runs on 12 volt power without the fuse holder getting warm – I know because I ran it for a while to check.

I reinstall the refrigerator back in the cabinet and go back to sitting around and watching the Rio Grande go by. Even with Roadtrek no longer in business, it's possible to keep these campervans running by thinking things through, analyzing the situation, and improvising when necessary.


RV Lifestyle

Published on 2019-04-09

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