I did a bit of searching on this forum for my issue but only found one thread that was fairly old so I will start a new one.

I am working hard at keeping a 94 Dakota alive. I noticed the voltmeter swings around rather wildly depending on the draw. For example, turning the blinkers on made it swing from about 14-10 volts with each blink cycle. I thought maybe the wire going to the voltmeter is just a bit light. But I just noticed a new trick. I saw the meter was pointing more a 12 volts instead of where it should be when I was driving it. Turning the headlights on made it go even further down. Bad alternator was my first guess.

Nope! We hooked up a voltmeter to the battery terminals and it showed 13.8 when running and it did not dip with load.

Now when I turn the lights on, all the gauges go wacky. Speedo and tach go to zero. Fuel, temp, and oil pressure gauges hit the top. There isn't a single gauge in the cluster that doesn't go wild! Turning the lights off returns everything to normal.

Any ideas or tests to perform?

Thanks,
cortman

 

My truck does that too sometimes. I figure its a weak ground or an intermitent short, give it a couple good smacks and see if the gauges come back.

 

I didn't really try anything yet, but my brother is sure it would be a bad ground somewhere. It was nice and cold this morning and the gauges were all back to normal. Hmm.

 

My truck did something similar years ago.

Happened occasionally/randomly.

Sometimes the truck would literally die, like someone unplugged the whole thing.

I found when I took the dash out. The idiots who installed a remote starter, had done a horrible job, and one of the wires, which they had spliced into, was shorting on the steering column support below the cluster.

I looked deeper after finding that, and discovered more serious flaws in the remote starter install.
Biggest one was, one of the main power wires had no insulation on the splice for the remote start.
I'm lucky the thing didn't catch fire all those years of weird intermittent symptoms.


Check all the connections you can. Especially any aftermarket ones.