Major problem for GM experts

[gennacide]

I recently changed vehicles and wanted to put my old equipment into the new vehicle.

 

I am having 2 major issues:

 

1: My speakers are having a major problem with sound quality and fading

2: My amp fried

 

Details:

 

Audio Issues: Installed a Pioneer AVIC-Z3 into a 2006 GMC Yukon XL Denali (has premium boss and onstar) using a GMOS-04 harness interface. If I plug the harness into the Pioneer's RCA outputs once the volume gets louder it starts to fade from front to back over and over and over. It also will only go to medium volume before it starts to peak. I tried using a high quality 4 channel LOC (line output converter) and it had the same problem. Only after hours of trial and error did if find a solution to my problem. I put the rear channels into the non-fading output of my Pioneer deck and the Front channels into the LOC. This worked great, only problem is that I lost my subwoofer output So I decided to just connect the subwoofer amplifier to the other 2 channels on the LOC.

 

This all worked perfect for about 3 days. Then out of no where I was driving around listening to music and very low volume when my dog slammed into the glove box as soon as this happened (don't know if that actually caused anything or not) my subs started making this popping noise and eventually blew the in-line fuse. (there are no fuses on my amp). I determined that the amp had been fried by going to a car stereo store and having them test the amp.

 

 

I have come to the conclusion that it was 1 of 4 things that blew the amp.

 

1. Improper grounding (using seat bolt)

2. LOC caused surge through RCA cable

3. Alternator surged power to amp

4. Something to do with the crazy fading problem

 

Equipment I am using:

Avic-Z3

peripheral 4 channel line output converter

Metra GMOS-04

Powerbass ASA 1500.1D Amp (now fried)

2 12" Memphis M3 subs

 

Here is a wiring diagram:

http://tinypic.com/view.php?pic=dwf6o6&s=7