[BlackStallion88]

I just bought an 87 GT with some electrical problems. The cruise doesn't work, the power locks don't work, on the driver's side window control panel I can't control the passenger window. Lastly the gas gauge seems to bounce around at times. Also, I don't think the engine temp is working on the instrument cluster. Is there any common ground with these?

 

[kbernal1016]

I would start by checking all the fuses and ALL the ground. Youre going to need some wiring diagrams.... Be patient though, electrical isnt hard, its just time consuming.

Check all the aftermarket stuff that has been installed in the car too, sometimes people do some WIERD stuff.

 

[87GT Drop Top]

The cruise is probably the servo. The fuel gauge sounds like the slosh module. As for the windows and locks, the switches are probably corroded. Remove the switches and take them a part. There are contacts in there like points on an old car. Go to a parts store and get a point file and file them clean. You will have to grind the file down a little to get it in where it needs to be.
Good luck

 

[b-blown]

for the windows it could also be broken wires between the door and body in the "boot"

 

[BlackStallion88]

Thanks for all of the help! I will keep you informed