My 91' Firebird has no main power to the stereo. When I bought the car there was an aftermarket head unit in the car that had no constant, whenever I would shut the car off I would lose presets, etc, but I didn't care too much since I planned on going back to a factory tape deck. Well, got my delco tape deck ready to go, I pull the old stereo, and found that the yellow wire was bridged to the the red on the aftermarket adapter, bypasing the orange main. I removed the adapter and hooked up the Delco and Nothing! I know the Delco head unti is good, since i hooked it up in my friends 94 blazer and it worked great. I got my test light out and checked my ground and my yellow ignition wires, both are fine, the orange wire is dead. So naturally i pulled the stereo fuse and tested the prongs in the fuse recepticle, which were fine, I replaced the fuse and tried again, still nothing to the orange wire...so what should I do next?

 

common problem in these cars, i was never able to locate the fuse to it, so i just ran a fused line directly from the battery

 

It works fine now, the previous owner probably had the same issue and spliced wires to get around it...it turns out there was a single, insignificant looking fuse labled ARC on the fuse box that had a blown fuse in it, replaced that fuse and now I've got power. Lesson learned; always check the thing that you suspect has nothing to do with what your trying to accomplish...

 

ill have to check that on mine. just for future use

 

I was gonna post the exact same thing I had this problem too and the only reason I found it was my service manual. I really don't understand it since the only thing this fuse does is run constant power to the radio.