Car Stereos: AUDIO HOOK UP, rear cargo area, using a multimeter

Question
QUESTION: I HAVE A 2002 ENVOY WITH BOSE I THINK. IS THERE A WAY TO SPLICE INTO THE WIRING HARNESS UNDER THE REAR SEAT? I DID THIS BEFOR IN A TRAILBLAZER. CAN YOU HELP ME WITH THIS

ANSWER: Hi Scott,

I'm assuming that you're trying to splice into the factory speaker wiring, to add an after-market amplifier to the factory audio system.  Is this correct?  If not, please let me know exactly what you're trying to splice.

The rear speaker wires can be found at the base of the B-pillars, where they run up into the rear doors.  I'm not sure whether they can be found under the rear seat; you should certainly be able to find them under the door sills, though.  The wire colors are light blue and dark blue on the right, and dark brown and yellow on the left.  Speaker wire pairs in GM vehicles are typically found twisted together.  Be careful, though, because airbag wiring may be found in the same locations, and you definitely don't want to tap into those.  You can identify speaker wiring using a multimeter set for AC volts; when the speaker is playing, you'll see AC voltage on the wire that increases and decreases with the audio volume.

Personally, I'd go straight to the Bose amplifier to tap into any speaker wires.  It can be found under the side panels in the rear cargo area, usually on the passenger side, but in some models on the driver's side.  You'd need to remove the entire side panel to access the amplifier, but it's worth it because you'll have easy access to all speaker wires.

Hope this helps!

Brian



---------- FOLLOW-UP ----------

QUESTION: Do you happen to know which is positive and which is negative?

Thanks again,

Scott

Answer
Hi Scott,

As a general rule in GM vehicles, the lighter wire color is positive in the front speakers, and the darker color is positive in the rear.  So for the rear speakers, the positive wires would be dark blue and dark brown.

Hope this helps!

Brian