HELP..C6..Poor FM & Dimmer not working after Kenwood HU install

speedy77 · 03-20-2010, 09:13 AM

I just did a clean sweep of the stereo in my C6Z, HU, amp, speakers. I installed a Kenwood DNX5140 HU. The FM reception sucks compared to the stock unit & the dimmer doesn't dim down at night. I believe I have the setting right in the unit & all connection made to the GMCO. I did go from a CD changer to Nav unit.
Any advice would be appreciated.

Thanks, Steve

I think I found the dimmer problem, needs to be hooked the gray wire for the TC......correct ?

markcz · 03-20-2010, 10:08 AM

Correct for the gray TC dimmer wire

C6 has a powered antenna module in the rear of the car. It is normally powered by the radio via the same circuit that powers the stock amp. I'm guessing you connected the 'remote amp turn on' from the new HU (blue/white) to your new amp, but didn't also connect it to the blue wire on GMCO (connected to white wire at B3 of the main radio harness). In your situation, I'd connect the 'power antenna' wire from the new HU (blue) to the GMCO blue wire since you only need it to come on when you play the radio. Then make sure the settings on the HU turn on that wire when you play AM/FM (if it can be changed).

C6 radio schematics are available here, check out the antenna schematic.

speedy77 · 03-20-2010, 11:30 AM

Quote:

Originally Posted by markcz

Correct for the gray TC dimmer wire

C6 has a powered antenna module in the rear of the car. It is normally powered by the radio via the same circuit that powers the stock amp. I'm guessing you connected the 'remote amp turn on' from the new HU (blue/white) to your new amp, but didn't also connect it to the blue wire on GMCO (connected to white wire at B3 of the main radio harness). In your situation, I'd connect the 'power antenna' wire from the new HU (blue) to the GMCO blue wire since you only need it to come on when you play the radio. Then make sure the settings on the HU turn on that wire when you play AM/FM (if it can be changed).

C6 radio schematics are available here, check out the antenna schematic.

When I was doing the wiring I did have it connected to the blue GMCO wire, but another forum member said hook it to the amp turn on wire. At that point I tried both ways, radio reception was the same either way (but I didn't move the car, just tried it in the garage). I left it hooked to the amp turn on. Do you think it would make a difference hooked to the blue GMCO wire that plugs into the B3 ?

Also I have both plugs disconnected at the Bose amp, does that matter ? I tied all the black ground wires together, should them be run to ground ? Thank You !

markcz · 03-20-2010, 11:55 AM

The stock amp being unplugged won't matter.

The blue gmco wire connects directly to the white wire at B3 of the car harness. That white wire connects directly to the antenna module to power it. If you don't have anything connected to the blue gmco wire, your antenna module is not powered.

Powering the module may not help much, but it will help.

Use the blue antenna power wire from the HU harness on the blue gmco wire and make sure the power antenna settings are correct, that will be as good as the stock antenna can get with an aftermarket HU.