Strange Signal/Electrical Problem

[dachrist]

I have something going on in my 99 Tahoe that is very strange. Recently, when putting the turn signal on after driving for a bit (say 5 mins or so), the voltmeter will drop to 8 volts (from 14), then quickly raise back to 14 volts. It doesn't matter what signal (left or right), and it doesn't always do it. Sometimes the drop in voltage is also accompnied by the dash "resetting" itself, IE all the idiot lights come on as if I have just started the truck, and the temp gauge in the rearview mirror also resets (shows 100 and then goes back to correct temp). The strange thing is that it doesn't always do this, only after driving for a bit without using the signals. Does anyone have any idea where I should start looking?

 

[Ceejkay]

how do the connections on the battery, alternator, fuse block wires, ground wires look?

 

[blizz]

Mine blows the signal fuse when I use my left blinker. Still haven't figured it out yet.

 

[SunlitComet]

re-seat the connector on the gauge cluster and harnesses below the dash.

 

[dachrist]

Ok so I checked all the wires, grounds etc and all were in excellent shape. I am still having this problem. The weirdest thing is that it is hit and miss, everything is fine when I first start the truck, almost until it warms up. Then sometimes when I put the signals on, the voltage drops, and sometimes it is fine! I also noticed last night that when the headlights are on and I put the signal on when idling, the headlights dim a bit in time with the signals.

 

[SunlitComet]

It has to be a weak alternator/bettery or a bad connection you have not found the main grounding points were on the right rear of engine compartment you should see them on the frame rail to body and engine. Have a shop or part store perform a load test to eliminate the starting and charging system as a cause.

 

[dachrist]

Ok I thought I would give an update on this. The problem was getting worse, even turning on the headlights would cause all the idiot lights to come on, and now I even had a slight engine stumble when hitting the blinkers (only sometimes though, which was very frustrating). Then the truck became hard to start (but not always). Checked and double checked all ground connections, all were in great shape. I then decided to check the positive connection on the battery, and it was FULL of corrosion...really really bad. Took everything apart and cleaned it up, used lots of dielectric grease when putting it back together, and now everything is perfect again.

So the morale of the story is make sure you check ALL connections, even the positive side!

 

[SunlitComet]

don't use dielectric grease and battery terminals. They have protective spray for that.