Thread: Help with aftermarket radio!!!

When I got my 05 grand prix, it did not have a radio in it at all. I bought an aftermarket radio and took it to best buy. They installed the radio, and then afterwards told me that the insturment gauges would not work because the computer in the car was searching for the factory radio. I don't understand why the gauges worked without a radio in it at all, but then they put one in for me and all the sudden none of my gauges work properly. You can just be driving down the road and all of the sudden the speedometer, rpms, temperature, and gas all go to zero and won't go back until you restart the car. They said if I buy a factory radio they can wire the radio to the trunk and this will fix the problem.

My questions:
1. Is this true?
2. If it is true, can I buy a factory radio that doesn't work or does it have to be a working factory radio?

Originally Posted by REDCOMPG

Best buy guys are morons.


The only thing that would not work with a aftermarket radio is going to be the calendar feature on the DIC you can keep features like door chimes,onstar and steering wheel controls if you get the correct harness/module.

And what do you mean by gauges?

I mean the speedometer and the temperature gauges and the gas gauge and the RPMs. They all go to zero like they aren't working. They won't go back to normal unless you restart the car. it didn't do this before they put the radio in. If the computer was searching for a radio, why would it not have done this before when there was no radio at all?

Even the low fuel warning on the little computer screen comes on, even though I know I have gas.

Originally Posted by Linus M

Look up GMOS-01. It's a wire harness that is required for any aftermarket radios on the 04+ cars. (there's a couple others out there, but that's what we use at the shop here all the time and have always had good luck with it.) If the Best Buy guys didn't put one in or put in a non-working one (it's been known to happen), it'll cause all sorts of random issues with those cars.

My guess is the Best Buy guys put in the wrong harness (or a non-working one) and when they couldn't get it to work made that up as an excuse to get you out the door. Aftermarket radios will not cause those issues if installed correctly with the proper wire harness.

So, if he replaces whatever he used with one of those it should start working again? I'm just frustrated, I can't drive around without working gauges!

Originally Posted by rperry435

First off the radio interface modules for the 04+ grand prixs DO NOT WORK PROPERLY.

they will for sure 100% cause data communication errors.

Pull that **** out and just hook the red accessory off the aftermarket radio to the wiper fuse (easiest access for a rap circuit to turn the radio on) or any accessory/ignition wire.

Without the module you will lose chime, onstar and the date in your dic that's it. This is assuming you don't have monsoon, os04 is required for monsoon and the os01 will not work properly

Sent from my Galaxy SIII on Tapatalk 2

Thanks. What is monsoon? My radio is a Kenwood!

I don't care about maintaining anything except for my speedometer, gas gauge, RMP and temperature gauge!

No. I have two speakers on the front doors that don't work, they are factory speakers. The car came with two aftermarket speakers in the back that do work.

Originally Posted by rperry435

Ok well if no speaker on the dash your grand prix didn't come with the factory upgraded monsoon system.

You don't need any module. Remove the module in there and hook up the accessory off the radio to the wiper fuse. That's probably the easiest for you.

Sent from my Galaxy SIII on Tapatalk 2

What is a module?

im kind of lost im about to hook up a aftermarket radio and i do hve the speaker in the middle i tried to hook up the stock radio and i notice no sound wires r cut from the factory amp but i had power no radio station came on i put i cd in it took it but didnt play so any help fellas