ok we just bought an 87 Trans am as a new project. I suck with electrical. PLEASE help me out. This is what everything does that ive noticed

-when you turn the dimmer switch up all of the gauges drop
-none of the gauges seem to be registering correctly
-speedometer isnt working (i think its probably the cable)
-turn signals flash slow as hellllll
-with the parking lights on the turn signal indicators light up solid and the turn signals dont work, and the voltage drops pretty significantly
-with the lights on the turn signal indicator light solid and the turn signals dont work, and the high beam light comes on. If you put the high beams on the light goes off. The voltage drops even further with the lights on.
-none of the gauges will illiminate except for a split second if you have the lights still on and you shut the motor off.


I haven't gotten a chance to rip the dash apart but i was going through the bag of receipts the guy gave me and i found that he bought pretty much every gauge part from a junk yard. So i have a feeling im going to find all kinda of ghetto-fabbed wiring.

 

Your looking at the old DIY remedy here since there are possibly multiple problems, especially if the dash and accessory wiring has been transplanted or replaced by a back yard hack? Same's true for the speedo. Check to see if it has a vehicle speed sensor on the trans tail housing before you assume it's a cable. Either way, you'll be able to better determine from there. Otherwise, if the wiring looks clean, check the grounds front to back and refer to a good wiring schematic. Time to learn electronics.

Good luck

 

Wade is right, this sounds like another case of a bad ground for the instrument cluster. Either a bad connection on the back or a bad wire to the chassis.
Pretty common.

Hope this helps.
Lou

 

well the entire interior and the dash is out. I found what i expected. It was the blue tape masacre. Everywhere i saw blue electrical tape there was like 5 wires spliced to one underneath it. And i guess the previous owner had subs in it. What i found was desturbing. The power wire for the amp was connected DIRECTLY TO THE STARTER. The speedometer isnt working because when the car was swapped from efi to carb it was done half assed and the never made the speedometer work. I dont know how many of the other problems electrically are connected to the motor swap, but the more i dig, the more problems i find.