Hey, I'm in the process of installing a pioneer 4000. I'm using a Metra harness but I think that's irrelevent. Anyway, when I probe any hot 12v to either the bose amp ground or the radio ground in the stock harness, I only get 8-9v ... and the radio won't kick on. If I ground directly to chasis, I get the correct 12v and everything works.

I'm just totally confused as to why the stock ground wires in the car are only giving me 8-9v? Thanks

 

try sliding the radio in the dash see if comes on

if not make a new ground

 

just ground it behind the radio somewhere.... problem solved

 

I remember grounding mine where one of the screws went with my Kenwood unit. Had no issues.

 

Mine has been grounded to the harness for 6 years now with no problems. Swapped out between 4 different head units so far.