I put in an aftermarket radio after my factory radio went out. It's a cheapy dual from walmart. I've developed two probs:
1: The radio blinks once the engine is off or even while driving if the radio is off.

2: The Alt,Bat,Hi-Beam,abs, fuel guage lights all start to blink erratically after about 30 minutes of driving with the radio on.

I've check and rechecked the radio wiring. I'm thinking it's a ground some where. I'm using the factory ground for the radio. and a ground on the rear driver side wheel well for my kicker box amp.

2004 blazer
59000 miles

 

Could it also be where you're grabbing your power from?

 

did you cut the wiring or did you buy the adapter for the radio???

 

Do you have any pics of how you wired it? The ground wire for your amp kit might be grounding out and shorting things out