Okay so I just bought a 96 blazer with an already after market head unit in (wouldn't turn on so I went looked like it blew up there was rattling pieces in it and the back end looked rusted out but I hooked mine up and the same thing it won't turn on so my question is...

He had the yellow (12v constant) with the orange (dash illumination) hooked together from the CAR to the HARNESS then taped that to the yellow wire from the HARNESS to the CAR. Is this right? Everything else matched up fine.

 

Is there an adapter harness being used or did the previous owner hack up the original dash wiring?

There shouldn't be ANY two different wires joined together, if there is, there's an issue somewhere else, be it a blown fuse or something. It makes no since to tie the dash illumination to the 12v constant, because then all of the dash lights would stay on all the time even with the truck shut of... Yellow should go to yellow, red should go to red, black should go to black, orange should go to orange, there should be no splicing two different colors together. Unless you're getting into installing a double din unit and you're trying to do some sort of park sensor bypass, but then that's a difference story :P

 

Wow god I feel so dumb right now... Well I seperated them and just crimped off the illumination wire to see how it worked still nothing so I decided to double check the fuses and wouldnt you know... The kid (only god knows why) put a 25 amp fuse in when it's supposed to be a 20... Now it works fine... Thanks for the help if you hadn't mentioned the fuses I would have had to drive 6 hours today with no radio and probably would have blown my head off... Thanks again

 

haha glad I could help always start with the simple things first, a fuse is a fail-safe so usually it's going to be the first thing to go bad, so it should be the first place you look