dieseldel

On my long vacation all at once the tachometer went to zero, the lights dimmed, the voltmeter dropped a lot, but no other changes. :'( I was about ready to pull over after a couple minutes, when the tach came back to life and the voltage went back to normal. Never has done it since.
I can't find anything shorting. It would take about 40 amps from the electrical system to get that much voltage drop.
Anyone have a clue on this? Must be a short, but in what?
Something else too. The clock display in the radio, and the overhead temp gauge fluorescent display flash bright sometimes instead of being controlled by the dash light dimmer at night when the lights are on. Enough to drive you nuts.
Thought I remembered a thread on here where someone had the flashing clock syndrome, but can't find it now.
Gotta fix it, I like my ol' 1997.
-Del

Mexstan

Sounds to me like you have two seperate problems. Would be surprised if they are related, unless they both started at the same time.
Problem one: I am going to guess that you had a temporary short in some primary wiring. If it were a problem in the secondary wiring a fuse would have blown with that amount of current draw. Suggest you follow the wires from the battery thru the firewall and see if there is any sign of charing. Were you by any chance on a bumpy road when this happened? It may also be something inside your alternator that is starting to go south. How old (miles and years) is the alternator?
Problem two: Again will take a wild guess. This could be something as simple as the dimmer by the light switch starting to go bad. If you can remove the dimmer easily, take it out and spray the interior of it with some contact cleaner. Work the dimmer (rheostat) from stop to stop a few times. Check for loose wires or bare wires contacting one another near the dimmer.
Let us all know what you did to fix both problems.

dieseldel

mexstan:
the alternator was new March of 1997. 129,000 miles ago.

Okay, I'll try to check out those things. Problem 1 could be the alternator, I suppose. It did get a lot of oil into it early in the trip from the guy who did the KDP fix not properly tightening up all the gear case bolts. Got oil all over the belt and everywhere, of course.

-Del

TGCTD

Heater relay stick? Was the temp low enough to turn on the intake heater?

dieseldel

Update on the strange electrical problem.

All the electrical problems I described turned out to be the headlight switch.
It was not making good contact on some segments, which heated the terminals. That caused burning of insulation on not only the switch itself but the wiring bundle, so there were shorts in the bundle. There are fuses on the circuits involved, but overall, not individually on each wire, so it could draw quite a bit of power without blowing a fuse. It sure did fry the switch and wiring. Dodge dealer had the wiring bundle and switch in stock and acted like this is normal. hmmm. 130,000 miles and counting. Nice to have my tail lights bright again. They had been kind of dim for 20,000 miles at least.
The headlight switch can affect a LOT of circuits if it starts to go.
-Del

Smokee

I hope the dealer didn't make you pay for the switch! It is a recall item.

Mexstan

Glad to hear that the problem has been resolved. Thanks for updating us. More guys need to do this once they resolve their problem(s).

RAM-RED

Smokee,

What recall is used here?

RED-RAM

JKM

I don't think it was a Recall , but a TSB.

Go HERE and enter the last 8 digits of your VIN in the box to check for any unperformed recalls.

fschiola

Actually there was a recall on that truck year and model.
Click
You should not have been charged for any of the work.