Ok this if for all you pioneer HU users who are getting a very annoying alternator whine. Its most likely not your fault. Thats right its a manufacture defect. The internal ground is fused. When this fuse pops then good luck getting a ground. This will lead to that very annoying alternator noise.To solve this all you need to do is jerry-rig the ground. When I got my pioneer and was dissapointed with the noise. Sold it made a bill and bought a higher end premier. Same problem existed. I dealt with it and then sold the deck. I bought another high end premier with the same problem. My Alpine had no problem. So i was like this is not a coincidence. I googled it and found this pic. Just do what they did in this pic and your set.

http://audioforum.termpro.com/topic/18/2066.html

NOTE: THIS IS NOT MY WORK O AND PLEASE STICKY

 

dude u couldve just bought a ground loop isolator

 

bought one at best buy but it only reduced it slightly not wortch a cent also quality dropped it got all flat, had 2 pay some money, and i would have to buy one for every pioneer i installed also this is so much more simpler and healthier for the deck since now its actually grounded.