OK here is the deal. Turn on my truck everything works fine. As soon as i flip on the turn signal everything except the speedometer goes dead.

1987 22re pickup.

I've checked all the fuses. Unplugged and replugged the whole gauge panel.

Any ideas??

 

Check the grounds, main cab ground is a screw into the sheet metal behind the driver's side kick panel. Might be your other devices are finding ground through the turn signals and when they are turned on they lose the ground, or vice versa. And don't just look at the screw and say it is OK. Actually remove all the wires, wire brush the ring terminals, make sure there is no paint under the screw, then reassemble. Also check the flasher relay, in panel near ground screw.

 

I have a similar issue. When i hit the turn signals my speedometer sweeps to zero and then sweeps back to my current speed. Ground issue as well?

 

One way to find out, check the grounds and see. And if that does not work, probably need to break out the volt meter and see what is going on.

 

Sounds like a plan. Im in my dorm right now and my truck is about a half a mile walk. lol I'll check it and repost what I found out sometime later today.

 

Cleaned up the ground. Nothing is fixed. Where should i start with my voltmeter?

 

Measure the voltage at the power and ground connections of whatever things are shutting off with the turn signals. If those are dropping, trace the circuits back, like measure the voltage at that circuit's fuse and go from there.

 

Fixed! Took care of previous owners very bad wiring, generally cleaned up all the wiring in general and i must have accidentally fixed whatever was shorting out. I love it when a plan comes together!