Van Electrics

Motorhome electrics really piss me off. Fuses are located all over the place, as are relays, and it's particularly difficult to locate them on old motorhomes, even with wiring diagrams..

I've had a long-standing issue with the van fridge not running on 12v when on the road (it runs on 240v on hook-up, gas when there's no hook-up and 12v when driving). I went through every fuse in the damned thing and replaced just about every relay I could find, but to no avail - or so I thought.

The van's 12v fridge supply only works with the engine running but, during the process of fuse and relay replacement, I forgot this and ended up testing it with no voltage actually being generated. 

I also had a 12v ceiling light that wouldn't work and I couldn't figure out why. I confabulated the two issues of the fridge and the ceiling light into one, common problem, thinking that they were on the same circuit, but couldn't figure out how or why. Switching the bulbs from the working light to the failed light showed that it wasn't the bulb that was blown, so I continued hunting around for a fuse I'd missed. 

As for the fridge, I read on a forum that the fridge only worked with the engine running and so, having forgotten this nugget, I switched on the engine and - hey presto - the fridge worked. One of the fuses or relays I'd replaced had done the job, but I'd forgotten that the engine needs to run for it to work.

The ceiling light failure, however, was still a problem. The wires in the light bore no resemblance to the colours shown on the wiring diagram, demonstrating they'd been replaced at some time in the past. Given all the interior lights appeared to be on the same 12v circuit, it suddenly struck me that perhaps it was the light switch that was at fault. I shorted the switch wires and - hey presto, again - the light came on.

Now it's impossible to get an identical light fitting in brass effect, so I've ordered two new ones with much brighter LED arrays in a carbon fibre fitting, which will go well with the interior decor.

UK made, of course, not Chinese.