I recently replaced my monsoon amp because it died and now this new one died too. I decided to go with an aftermarket radios because I'm fed up with this monsoon crap. I installed the radio but for some reason I only have the rear cargo tweeters. No other speaker works. I used the Scosche GM02B / GM02. I also ran a volt meter on the wires coming from the radio, after the adapter harness, and at the plug for the amp, all with power. I can't figure this out.....

 

You need to bypass the monsoon amp

 

I've never heard of two Monsoon amps going in a short time. They are usually quite reliable unless pushed beyond their (somewhat limited) output capability. Head unit, yes, but not amps.

Anyway, all of the speakers on a Firebird are powered by the amp except the tweeters (doors and hatch) which run directly off the head unit. So if your amp is bad, you should still have front and rear tweeters working.

pentavolvo is correct - merely installing a new head unit with the proper adapter harness has no effect on the Monsoon amp... it's still powering most of the speakers. If you want to eliminate the amp, you have to rewire the speakers to run off the head unit directly.