Electrical Problem Whack-a-Mole

Nothing.

The furnace and the A/C are dead. A quick panic set in, but on investigation the only other damage I could find was the outside porch lighting. Odd.

The wiring in this old beast is a bit of a mystery to me, mainly because so much of it seems buried inside inaccessible walls. It’s also important to realize that unlike a house, which has a single power system – 120v AC, or a car, which is basically 12v DC, RVs are hybrids, with both 120V AC and 12V DC, which can be interconnected in a number of ways, often multiple ways on a single vehicle, and with different approaches being popular over time. There are various inverters, generators, 20, 30, or 50amp hookups, low amperage power coming in from the truck, and more. I have a decent understanding of these things in theory, but since I didn’t build it, nor did I get a wiring diagram when I bought it, so the exact workings are largely a matter of speculation and assumption.

I spent an hour climbing around underneath the trailer, trying to trace the 12v power system from the umbilical that connects to the truck, the deep cycle batteries, through various harnesses, distribution boxes, fuses and relays. Also, my handy multimeter, was in the truck, across town with wife and baby. I found lots of new parts, and formed a mental image of how I thought things were wired, but without my tools and parts, I was powerless to fix. So I waited.

When Stephanie got back she was beat, but I walked her through the issues we had to tackle before we even got back to fixing the truck and its radio. After some contemplation, she recalled the previous owner pointing out a breaker panel – something I had unsuccessfully looked for that day, and thought was conspicuously absent, but had chalked it up to prolific and inconsiderate use of small fuse boxes and inline fuses. In a couple hundred square feet, it’s hard to hide things, but it turns out it was right in front of me the whole time, sandwiched between the bathroom door and fridge.

Opening it up, there she was: a burned out 15amp fuse. A quick trip to the spare parts bin for a fresh fuse, and we had power to the A/C, furnace, and porch lights again. Whew!

The next morning was Sunday in Nashville, which as it turns out means that nothing is open except churches, so I decided to take a stab at figuring out what was wrong with the stereo in the truck. I pulled the dashboard apart, yanked the radio out, and started probing around. It was a mess back there – the installer we paid generously did a really poor job, which is of course hard to tell after the fact when a dashboard is hiding the mess. We paid for a plug-and-play wiring harness, but he seemed to have pocketed that and instead crimped the couple dozen wires by hand. There was a lot going on, but all I cared about was seeing if the radio was getting power, so it was just three wires I cared about: ground, battery, and ignition-switched power. Ground and battery were fine, but no matter what – off, engine running, or just ignition switched on – the switched power was dead. That was a good sign. I mean, it’s a bad sign, but at least I had a cause I could focus on.

I bypassed the switched power, but still the radio was mostly dead. It sounded like it was trying to move its eject motor, and then nothing. The screen never even flickered on.

My working theory was now that I had somehow shorted the ignition line, and before the fuse could protect the radio it somehow fried its computer. Something like that. Oh, there was one big problem though: I couldn’t find any fuses that had burned out, so maybe the fuse on that line was overrated, providing no protection at all. In any case, it didn’t look good for the stereo. Fuck.

I decided I needed a professional opinion, so we hopped on Yelp and found a single car audio shop open on a Sunday. I put the car mostly back together – you don’t really need a dashboard cover while you drive – and we headed over, and got there just after they opened.

At the shop I approached the car audio department and was informed by a manager that they couldn’t help on service as their installer had died yesterday and his replacement wasn’t available yet. Yup. They helpfully noted that there wasn’t a single other shop open for installs on Sunday in Nashville except Best Buy, which we both knew I wasn’t about to stoop to. William was eager to help though, so in a Hail Mary I asked if they had the same model radio in stock, and he looked it up. Miracle of miracles, they had a single unit in all of their stores, it was in that very store, and it was installed as a demo model in a display their now-dead specialist had been disassembling. Seriously.

We walked into the back and sure enough, they had exactly my stereo, mounted in some painted plywood, still turned on. He offered it to me as-is, no backsies, for a steeply discounted price. After a quick consult with Stephanie I rolled the dice and bought the stereo, figuring at worst I’d end up spending just a bit more on it than I would have on labor for a shop to assess my problems. Also, it was Sunday, we were leaving Nashville the next day, and I wanted to make some progress, so we set our plans on hold and raced back to the campground with an exact duplicate of our busted radio.

I got everything swapped out, but I still couldn’t get it to start properly – though it was showing more signs of life when I tried, which was encouraging. Of course, I still hadn’t solved the switched power problem. I was frustrated as hell. It had to be a fuse, so I started pulling, checking, and reseating fuses again. Dozens of them. No luck. They were all fine. Filthy, hard to pull, but fine. Same for the fuses under the dash. Meanwhile, I had to repeatedly disconnect or reconnect the battery ground, and start and stop the truck, for testing.

Short of ripping out the factory wiring harness and tracing it all the way back to its source – a fools errand, bound to end with us stuck in Nashville with a dead truck and trailer – I was at a bit of a loss. So I decided, perhaps I could just ignore the dead wire and run another wire from a switched source, which in a truck like this are abundant.

I quickly realized I was short on electrical supplies – no connectors for the fuse block, no crimping connectors, I didn’t even have electrical tape, and I definitely didn’t have anything I felt terribly comfortable using to tap a power line unless it was an emergency, and this wasn’t one. I walked back to the trailer defeated, and we discussed next steps. We could stay in Nashville an extra day so I could go to a shop to have a professional deal with my mess, or we could put it all back together and drive to our next destination, where we could find a shop. We flipped a coin, and fate told us to move on and deal with it down the road.

This didn’t sit well with me. I hate unsolved mechanical problems. And then it hit me – I had bought a bag of “Add-a-Circuit Fuse Taps” on advice from a friend. These are a nifty little invention that, along with a spool of wire, was exactly what I needed to run another switched power line from the ignition to the radio. I rigged up a quick test, and it worked like a charm. I was in business.

I quickly finished up, making all the connections as secure as possible, and started to clean up. Getting the radio back in the dash was tricky – the wiring was messy and prevented the radio from sliding all the way back, but eventually I got it snug and put back together. The dashboard and kick plates snapped back in place, no extra screws leftover, and the new radio looked just like the old one. And the best part: when I turned the key, it turned right on.

That ABS light is still on though. But I’m starting to like it.