crazy HU install problems...read on please

[kalilay]

ok...i dont know really anything about pontiacs to begin with all i know are dsm's...anyhow my girlfriend just got a 1997 GA GT with 99k...stock radio and sony 6x9s in the back...i pulled the radio got a harness and a mounting kit like ive dont so many times before...and went to work putting in an old pioneer head unit that i have(and im positive it works)...so i get it wired up and turn it on...it powers on and reads cd's and tunes all that...but no sound?? im confident all my wiring is right ( i checked it like a hundred times) i even got another speaker and new speaker wire and wired it right to the cd player...still nothing...plug the stock radio back in and everythings fine???? ALSO...the cluster does not light up without either HU plugged in ...only if the stock one is hooked up...and if the stock radio is in...you cant turn the cluster lights off(dimmer doesnt dim)?? help please i hope its just something all you seasoned GM guys know all about and im just ignorant lol...thanks! sorry for the long story

[boug0752]

I know I have seen this problem addressed before in a previous post. I'll see if I can find it. Take a look through the search option and see what you can find. This is a fairly common problem occasionally for a lot of GA owners it seems so I'm positive we should be able to help you out!!

[Brandish]

You bought a wiring harness to connect it?

Because it sounds as though you've got one of your speaker leads connected to either the parking light wire or dimmer wire. It's easy to confuse these wires if you don't have a wiring harness to connect an aftermarket radio, because factory wiring colors for the dimmer wire is grey, and for parking lights it's brown. These also happen to be the colors of your front-left negative and rear-left positive speaker wires, respectively. I'd double-check your wiring. Disconnect all speaker wires for now, and then re-connect them with the HU turned on. You should start getting sound as you connect them. As soon as the sound cuts out, you'll know which wire is giving you the problems. Most aftermarket decks have a protection circuit that shuts off the internal amp if a fault is detected on any speaker wire. Factory decks do not have this, so they'll play happily until they burn up. Quality Delco products are good for this.