I installed an aftermarket stereo in my 77 this weekend but now I'm blowing the instrument illumination fuse. does anyone have a wiring diagram for the center dash?

 

The radio light is controled via the light switch rheostat (headlight switch) through the 5 amp "INST LPS" fuse. There is a dark green wire between the light switch and the fuse. From the fuse there is a gray wire to the radio for the dial light. At the fuse block there is also a connection between the "INST LPS" and the "LPS" terminal. The "LPS" terminal powers the seat belt warning.

The remaining radio wires are a yellow wire between the "20 amp RADIO" fuse and the radio (this is main power), A black radio ground, a dark green for the left speaker, a light green for the right speaker and two black speaker ground wires.

The 5 amp "INST LPS" fuse also powers all of the instrument lights which are controlled via the light switch rheostat.

If the instrument lights worked prior to the install, I would check the gray wire and make sure it isn't pinched and shorted to ground. If it is ok I would then verify correct voltage on the gray wire at the radio, it is possible the new radio has a internal problem in its light circuit.

I would also check the radio wire diagram and make sure you are hooked to the correct radio wire and the 5 amp fuse is the correct size for the radio light.
Hope this helps

 

Thanks for the info. I know it isn't the radio because I didn't hook up the illumination wire to the radio. The gray wire was kind of throwing me off though.

 

Note to self: Gray wire is not ground