To Hell With the Turmoil I'm Worried About My Truck

I had an 88 ford that had that happen, when it was doing it and you stopped it sometimes wouldn't start well. The problem was a wire corroded and felll off at the back taillight, one of the lights didn't work, and it would short out against the rusty metal intermittently. I noticed it and fixed it and the truck did not do that anymore. I just had to put a new brass end piece on the harness, getting the clip from another old harness I had. It could be almost anywhere in the lights. It probably isn't a diode, because the battery would go dead, but it could be a rusty ground wire to the engine or to the metal too, or corrosion almost anywhere. But it sounds like something is shorting out somehow the way it is acting on the gauge..

Good luck, you may need it, there are lots of areas that could happen.

a reply to: rickymouse

I have considered such. A loose, corroded, or hanging ground some where on the wire harness. I will do as complete an inspection as my patience will allow tomorrow before and after work.

Thought I should add that she made it cross state some 200 hundred miles after I bought her. Tired battery, 14 year old tires, and sick alternator. She is running great now compared to when I got her.

In almost every job post you may read, one of the first qualifications is a reliable vehicle. This is a reliable vehicle but she needs some TLC. She is for the job at hand, we need each other. Why do I love her rusted steel? Oh, pardon me for getting aroused.

a reply to: MichiganSwampBuck

Is the voltage jumping up or dropping? How long do the spikes last? Does the problem occur at idle or only when the truck is moving?

a reply to: MichiganSwampBuck

If you have a spare under the bed, there may be a ground under there. Had a dodge like that.

originally posted by: MichiganSwampBuck
a reply to: rickymouse

I have considered such. A loose, corroded, or hanging ground some where on the wire harness. I will do as complete an inspection as my patience will allow tomorrow before and after work.

Thought I should add that she made it cross state some 200 hundred miles after I bought her. Tired battery, 14 year old tires, and sick alternator. She is running great now compared to when I got her.

The hot wire on my ford truck going back to the taillight was hot all the time, they must have interupted the ground for the switches . I can't remember, that was a long time ago. I suppose you do not need the ignition on to run the flashers or brake light.

a reply to: rickymouse

Hot wires can go bad as easily as grounds I suppose when dealing with a randomly occurring electrical problem.

originally posted by: VictorVonDoom
a reply to: MichiganSwampBuck

Is the voltage jumping up or dropping? How long do the spikes last? Does the problem occur at idle or only when the truck is moving?

The voltage drops maybe 2 volts in bursts of maybe three or four drops. It then returns to a normal reading. The event lasts one or two seconds. I haven't been able to connect it to RPMs or uphill or during idle, it seems random except that it happens soon after startup (then driving) and happens every ten minutes or so. The battery reads normal before startup and charges like it should during operation.

ETA: Bumpy roads and vibrations don't seem to trigger this problem.

a reply to: MichiganSwampBuck

It sounds like something is trying to energize at regular intervals, draws too much current, then tries again later. Possibly either radiator fan or air conditioning compressor clutch.

Just spitballing here.

a reply to: VictorVonDoom

So you suspect that something along the line draws current and that the voltage meter is reading correctly? I still suspect the instrument panel is screwy, but I'm spitballing too, thanks.

ETA: It would be tough to connect a fan or other unit to this anomaly unless I spend a lot of time waiting for it to happen as it idles. Still a real possibility, thanks.

a reply to: MichiganSwampBuck

You could disconnect the electrical connector on the air conditioning compressor clutch and see if the problem remains.

You could run a jumper to the radiator fan so it runs continuously. Take a short trip and see if you get the voltage drops.

If you think it might be a faulty gage, I would attach a multimeter to a power socket or cigarette lighter socket. See if the readings match.

a reply to: MichiganSwampBuck

If you look at the bell housing from above, you'll see a wiring harness that runs along it. One of the wires in the harness has rubbed against the bell housing and is shorting, causing your voltage issues.

My ex had a Ford pickup that had this problem for months until the mechanic dropped his flashlight and noticed the sparking. Apparently it's a not too common issue so not a lot of people know about it.

90scarsonly here, if you had to replace a battery clamp due to corrosion then the inside of the cable is probably bad too. I'd replace the cable that had corrosion on the clamp and 2nd the idea about better ground cables.

There are a number of rusted grounds, I just found a braided ground wire that grounds a part of the frame together broken off and a ground on the trailer wiring that is rusted solid, there are likely more along the wire harness.

The engine light came back on as I thought it would, but it took better than 20 miles travel and it was unrelated to the jumpy dropping of voltage on the meter. That could mean almost anything and will need to be checked.

I'm taking it on a cross state trip today regardless, 200 miles to my destination. Hopefully it won't break down, I will be following another vehicle though. Cross my fingers and will report back tomorrow night.

Made it there and back. I'm beginning to believe it is an actual voltage drop, likely due to the fan turning on.

It consistently dropped a few miles after start up, then a total of four or five times on the 188 mile trip. Also, at a rest area, I was idling and I tested the high beam switch on the column a few times and the voltage dipped when I used it. So it seems that the meter is more reliable than I believed.

More important now though is the front end needs some work it seems, new shocks, a tire balance and rotation is due.

Why does love cost so much?

ETA: I'm considering some cosmetic work, she looked so good after I washed her before the trip.