Electrical Gremlins... - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 08-02-2000, 09:37 PM
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Electrical Gremlins...

I'm about five minutes away from torching my truck for the insurance money, so somebody, please help!

My trucks in an 84 Fullsize Jimmy, with a recently-replaced 350.

The first problem I noticed is that my indicators no longer work. I swapped the flasher relays around, and the Hazard lights will work regardless of which flasher is in which slot. No turn signals either way.

The second problem is that the the alternator keeps burying the voltmeter needle on the 18V side, every few seconds. This started 3 days after the above. The battery checks out at a little over 12 volts, and the acid level is fine. The stereo cuts out when this happens. This just started today. I haven't had it out for a long drive yet, so it may be the P.O.S. brake controller (See below) was shorting out and killing the battery.

Third -- Power locks no longer work. Even with the truck off, they click or clunk every few seconds. The doors won't lock or unlock, even with the engine running. I've had to disconnect these under the dash.

Fourth -- Moron, who owned the truck before me, decided he needed an electric brake controller for his trailer. I'm not even going to go into the wiring job he did, but needless to say it didn't seem to like being run at the 18 volts that the alternator was trying to feed it. I was able to scrape most of the melted plastic off of my left shin. To complement the wiring job, he installed the thing with stripped and bent flathead screws. After an hour of swearing in the most humid weather I've seen so far this year, I gave up and hacksawed it out.

The truck has been running fine for the last month -- I replaced the original (dead) 305 with a junkyard 350 in early july.

I've seen a few posts where people who've had engines replaced have problems like mine, and it ends up being a ground strap or something. I've managed to find one of these -- on the passenger side attached to the firewall. Are there more?

Does anyone have a picture of what the fuse box layout is supposed to look like? I can't read a single word on the box....It's all a big white smear. I want to know which fuse controls what....Horn, headlights, dimmer, gauges etc.

Any help is appreciated. Otherwise, keep a close eye out for my fire sale!


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post #2 of (permalink) Old 08-02-2000, 09:54 PM
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Re: Electrical Gremlins...

There are a few Grounds on mine (86 Chevy that I upgraded from 305 to 350) The negative (ground) cable on my battery connects right to my alternator bracket. There is another strap from the exhaust manifold to the frame. And the last from the exhaust to the firewall, as you had mentioned. Your starter draws the most juice (unless you have a Kickin' stereo), and it get's it's ground through the block. Hence, the block should have the best ground. But I'm not an electrician either!! I just spent three days figuring out that the problem with my dash lights was one of the traces on the electrical template behind the guages was cracked!! Good luck.

post #3 of (permalink) Old 08-03-2000, 09:44 AM
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Re: Electrical Gremlins...

That surge in power that you measured on the alternator is most likely the circuit breaker for the brake controller. I have been through two 30 amp breakers and they had the same symptoms (I think) that you are haveing. It would surge and the truck would nearly die when running. It is just a little piece too.

Nich Kenny
'89 K1500 350/700r4
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post #4 of (permalink) Old 08-03-2000, 11:10 PM
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Re: Electrical Gremlins...

I'm going to have to dig for more ground straps. I'm sure I only found the one, so that's likely the problem. Good news though, I hacked the brake controller out last night, and the voltmeter has been acting sane all day. <touch wood> Still no turn signals though, and I think the reverse lights are gone too. Tomorrow, I'm going to yank and replace every fuse, just in case.... While I'm under there, I'm going to get rid of the extra wiring that the previous owner had put in for the controller -- only four wires went to the unit, but it's spaghetti under the dash.... I've got no idea what he was doing -- I guess that makes two of us. Beyond that, I'm guessing it must be something in the column, since the hazards work fine.

Thanks guys!

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