Just got my 1987 Blazer recently. The only gauge working is speed. Also noticed there does not appear to be power to the circuit board that provides the display lighting. Is there a connection or bundle all the gauges that are run electrically go through? Anyone have access to wiring diagrams?

 

Anyone have a wiring diagram or know much about where the ground is for the cluster? Trying to eliminate the east first.

 

If the speed is working, its not a ground issue going to the cluster.
I would take the cluster out and look at the solder joints, GM is known to have bad solder joints.

 

Alright I will give the solder joints a look. I thought the speed was mechanic vs all other gauges being electrical though?

 

I am not sure with your 87. I know the 93 and 94 were electric.

 

Found some issues with the printed wiring card. Got temp gauge working.

Speed seema to have a mechanical connection and electrical.