Dash/Electrical help please
 

My old 72' non tach dash looked like "sheet" and the gas gauge and P brake (red warning ) lights were not working. I ordered and just got today a new reproduction black/chrome with tach and vacuum gauge set up from GMC Pauls. It looks fantastic everything works except what did not work before.....gas gauge and red warning lights also can get it to light up at in dark. All these are the same problems I had with the old dash cluster. It has got to be wiring.....no??? Anyone with any ideas?

Thanks

Where does the fuel guage needle sit? At way past full, or way under empty, or where ever you place it with your finger.
If it is Under empty, the brown wire is grounded somewhere...normally under the chrome trim in the door jamb.

If pegged, then your brown wire is cut or disconnected.

If it stays where ever you place it with your finger, then there is no power going to the guage.


*Brown wire is the one that goes from the fuse box to the fuel tank*

The red warning light is not for your parking brake-it is the light for brake problems in system. Look under your MC and there will be a tan wire going to the porp. valve. Turn switch on and unplug this wire and ground it. Red light should glow. If one side of your brakes go out(front or back) the porp. valve will ground and cause the light to come on warning you of a brake problem.

On my 72 the red "BRAKE" light does double duty. It goes on and off with the park brake and stays on if you have a brake problem. The brown wire goes to the prop valve and a switch on the parking brake

tom hand--did they come from factory that way? I have a 71 Cheyenne that did not have the parking brake switch. (added one to mine.)

Just got back from my mechanic friends shop....As it turns out the sending unit in the relocated gas tank is not working. I will order a new one tomorrow. As for the red brake light....it remains to go on and off...mostly on. I will try to determine what the problem is???

Thanks for any help so far!