I think mine is dirty cause my trun signal is tuck on and my tach and battery guage are dead also,it only happens when I turn on my lights,where is the ground???anyone??????????????

 

I had a similar problem, turn on headlights and both turn signals would illuminate constantly but dimmly. Guages did not function properly. May have been other little quirks that i did not mention, it's been a couple years since the problem was fixed.

Traced back to a bad ground under the drivers side dash close to the front of the steering column. Ring terminal had snapped around where the wire crimped in.

 

It is a ground problem, but the location of the problem is on the back side of the instument cluster.
I had this problem several years ago...all worked fine with the dash lights off, then when they were turned on, the right blinker indicator came on, the tach just hovered and the needle would move by adjusting the dimmer switch.
It turned out to be a break in one of the PC traces on the back of the cluster. I carefully soldered a jumper wire across the break and it has worked fine since. The spot on mine that was broken was near one of the upper dash lights where the bulb holder screws in.
Hope this helps....

Pete

 

Speaking of grounds, i just finished getting the windsheild wipers working on the bird.

First replaced the motor, then discovered that the new motor worked only intermittently much like the old one. Car is around 15 years old, so it seemed reasonable that the motor was worn.

I was now suspecting a bad ground, wiper switch, or corroded connector. Discovered that wiggling around the wiring harness in front of the brake booster made the wipers come to life and then wiggling it again they'd stop.

After looking at schematics I found that wiper ground was on the back of the drivers side cylinder head, very difficult to get to. Tapped black wire at bottom wiper motor connector and attached to an alternate ground location, problem was now fixed after much frustration.

Old style gm wiper motors have a ground path through the bolts that attach the wiper motor case to the firewall. Newer ones get a ground path through a seperate wire.