Electrical puzzle

Today's Brain Teaser:

I just bought an '87 Ford Ranger XLT pick-em-up and wrote the check and signed the papers before testing every possible combination of switching electrical devices on and off. After driving it around for a couple days I've noticed some very strange behaviors and I'm open to suggestions as to finding the gremlin.

1) It's possible that the aftermarket radio was installed wrong - I haven't opened up the dash to see how it's wired yet (waiting for the weekend). When I turn on the headlights, the radio cuts off momentarily. When I dim the dashboard lights the radio goes off completely. But, the radio works when the headlights are not on, which seems to rule out the possibility that the radio's power is wired to the dash lights. However, each time I turn on the radio the station preset memories have been erased, meaning that the memory power was never hooked up(?)

2) Sometimes, the first time I try to use the turn signals they don't work - but if I turn the hazard flashers on, then off, then the turn signals work fine. At least, until I park the truck and start it again, then the turn signals won't work until I do the hazard flasher ritual. Sometimes I can just start the truck & the signals work.

3) The fan for the AC/heat sometimes doesn't work at all. Other times it works fine.

Looking at the wiring diagrams, I find that the one thing that the fan and turn signals have in common is that both of their fuses are fed by the same copper strip on the back of the fuse block, which is, in turn, fed by a yellow wire from the main power harness.

How likely is it that I need to pull out and replace the whole fuse block? Does anyone know where I would find the other end of that yellow wire to do a continuity test or am I going to have to open up every wire loom and trace it out? Is it even possible to buy a replacement fuse block without digging another bad one out of the wrecking yard or having to splice in an aftermarket generic?

I've already decided that the best "fix" for the radio is to remove it until I get the other electrical gremlins solved - or see how many of them disappear when that radio is gone. There's no brand name visible on the front, but I get the impression that it's not a very good one.

Suggestions?

The first thing that popped into my head was a bad ground somewhere. The next thing was a flood car and you're in Houston.....

The first thing that popped into my head was a bad ground somewhere. The next thing was a flood car and you're in Houston.....

Oooh, you're not making me feel any better about this (lol)

Being not a native Houstonian, I hadn't even considered the possibility of a flood car. From what I've seen so far it seems a bit too clean to be a flood car; shouldn't there be a thin film of dried mud/ slime/ discoloration wherever it got wet?

I'll be disassembling the dash this weekend - thanks for your input.

I've seen this, Hes run the radio ground on the ground for the dash. Try turning off your radio and seeing if your other electrical items work fine...

I've seen this, Hes run the radio ground on the ground for the dash. Try turning off your radio and seeing if your other electrical items work fine...

Hmmmm <scratching chin>

Well, that certainly is something I'll look for when I get a chance to open up the dash Saturday morning.

Meanwhile, the other anomolies seem to come & go at random regardless of whether I've turned the radio on.

Although it does seem that the AC/heat fan is more likely to work if I turn it on first, before anything else.

Oddly, the problem with the turn signals seems to have disappeared, at least for now, without having fixed anything.

The Electrical Engineer that I work for has suggested that I may have to resolder the connections on the back of the fuse panel; but now I can't remember whether I still have a solder iron. It might be in one of the toolboxes under the cabinets.

Thanks guys.