VGC

So I picked up a JVC touchscreen head unit for the 2005 911 Carrera S. Got it from Crutchfield with all the necessary hardware… But of course nothing works right.

The problem I’m having is the wiring schematics. I’ve done tons of searches and can’t seem to find anything specific to that car, with the Bose audio, it has two wire harnesses from the factory, but you only use one of them in the installation.

The problem I’m having is between the ground/power/accessory wires. It appears I found them, brown, red/green, and acc. The two larger ones, brown seems to be the ground and the red/green seems to be the power… But when I connect everything, the head unit doesn’t come on.

There’s only three wires going into one of the harnesses and it’s crazy. What the heck is going on. It has the fiber optic bypass wired, but I can’t get the unit to go whatsoever and I can’t seem to find anything online to help.

any thoughts on this? Supposedly you’re only supposed to use the smaller of the two plugs. The one in the top of the photos.

CBRich

You're correct on the Red/Green and Brown/Brown power and ground. They are on Plug A below. Plug C is also pictured below. It does have a Wake Up, which is usually a switched 12V if I recall correctly. I would probe it to see if it provides power with ignition on. Really, the head unit only needs three signals to turn on. Usually black (ground), red (12V), and yellow (Acc / Wake Up / Ignition). If you have those three things to the head unit it'll work. Take a multimeter to the wires I mentioned and validate you have those three signals headed into your head unit.

Sylverlee

Only 3 wires is correct.

Boggus

Probably have to wire in a switched wire, ignition.

MarkTro

It you need more help, check out this thread. I found it helpful.

https://rennlist.com/forums/997-gt2-...l#&gid=1&pid=7