I had installed an after market Pioneer radio and a set of 10s with an aftermarket amp. It all works great but the new radio doesn't shut off the factory amp causing a 500 mA parasitic drain killing the battery in a couple of days. Pulling fuse #38 stops the drain but disables the factory speakers. Any ideas?

 

Review your install. Which adapter did you use?

 

Don't know because I had it installed where I bought the gear. Im going to visit them tomorrow

 

They used a PAC brand adapter which seems pretty standard.

 

The people that installed your stereo 'wired something wrong'
***They probably hooked-up the amp. to a constant wire
Go back and have them change the Amp. wire from constant !

 

Simple fix, install a toggle switch to the remote turn on wire for the amplifier.

 

pac systems seem to be buggy. alot of complaints on them

 

I had a lot of issues with the PAC harness in both our Escalade (Pioneer head unit) and H2 (Kenwood head unit), causing random issues with the speakers etc. I went with the Metra harness and it solved all the problems. Look at some of the Amazon reviews for the PAC harness in GM vehicles, a lot of people have the same issue. I don't know if that's related to your amp causing a drain though, that sounds like they wired it wrong or it's defective