From what you have said, im almost 100% you have a bad ground somewhere. Maybe its not the battery or frame grounds. Maybe its not the HID ballast grounds. Maybe its PCM grounds.

Bottom line is IMO you have a ground issue. If you disconnect your amps and your HIDs and still have dimming of the lights and such then they are not the issue.

 

Thanx for the feedback. Guess i need to do some checking.. So i guess from what you said your truck never had any dimming issues when it was stock.

 

Thats not alot of power at all, I could see slight dimming but not that bad. What size fuse do you have at the battery for your amps? What brand and model amps are they? Put a multi meter at your battery and see what tour voltage drops too when playing....then turn your hids on and check again.

 

I dont remember on the fuses without looking. I think they are 25's. All the audio is name brand. Alpine amps. I havent done the voltage check yet but will get to it this weekend. Thanks for the suggestion.