It's now 2024 and I want to add an OEM nav radio to my '05 GTP CompG. With the help of my 3 volume OEM shop manual, I've discovered a few things which should make this upgrade go easier. Following pertains only to '05 but maybe thru '08 as well and, with the VSS wire, not to GXPs. The VSS tap can be done more easily from the TAC module connector (Throttle Actuator Control). It's the same wire and circuit and the only dk green one here. Not so for GXPs. An issue that I've not seen discussed anywhere is the TAN amp control wire, circuit 927. Per the manual, on my car as it was delivered with no nav but instead the 6 cd changer, this tan wire is located in the smaller C2 connector F position which is just 2 over from D where we are going to plug in our VSS wire. On a US4 car (with nav) this tan wire is over in the C1 connector which is currently occupied on my car by a gray w/black "amplifier present signal" wire, circuit 2334 I suspect I will have to move the tan here and then just tape off the gray one since the manual does not show another place for it. Phew! I don't even know yet what to do about the two pink wires for voice on the nav but most likely won't exist currently. A more troubling issue for me is that only the '08 nav owner's manual gives instructions for steering wheel controls. So if any of you out there have an OEM nav in an '05 and the steering wheel controls function please reply back. I purchased from ebay an '05 Pontiac original oem nav for myself for Christmas - with all the connectors and cut wires but won't get at this until it warms up! Trying to get list of all Denso navs with features.
OK, here it is July 2024 and the nav radio is installed and working beautifully. The two amp-related wires were moved per earlier entry. Forget the dark green vss wire. Without it I don't have: speed compensated auto volume control - who cares? Time to destination - who cares? The vehicle position is herky jerky instead of smooth, as the GPS signal updates about once every 2 seconds or so - again, who cares? For the last couple of months the GPS antenna hasn't even been mounted solidly, just tucked in above the radio. And unless I find the short harness for the voice activation, it won't have that either. You guessed it - who cares! The radio is exquisite looking and the steering wheel controls work like they're supposed to. Why didn't Pontiac make mention of them in the '05 to '07 nav manuals? I have a full color wiring diagram complete with notes and changes. Just pm me and I'll email you the .pdf free. NOTE: Corvette radios for this period are identical and it's my understanding that upon clearing the vin and relearning, the Corvette logo automatically changes to the Pontiac crest. But their radios have an extra wire for an FM composite signal which I don't understand.
