Five Wire Heated Power Mirror Wiring

[campionc]

You can see my original post here:
http://www.thedieselpageforums.com/tdpforum/showthread.php?t=44014

I originally meant to post this as a new thread instead of putting it as a reply in the original post since it's a little bit different and more defined now, but I'm unable to go ack and delete it.

Anyway, I think I got most of the wiring diagrams figured out as to how the 98 mirror switch should interface with the 99 mirror connector, keeping in mind that I will have to manually wire up the heat portion of the wiring harness to a switch, but there's one thing that'spuzzling me. My new mirrors state that they are plug and play for 99-02, but only have five wires. My understanding is that there should be two wires for the heat, and four for the motor controls.

I've looked at the AllData diagrams for the 98, but I don't have access to the 99 information. So, I'm unable to account for the discrepancy. The other diagrams for the 99 mirrors that I've Googled all have four motor control wires. The only thig I can think of is that there is a common wire that would be shared by both the heat and the motors, but I can't confirm this on my own.

I've looked at all the diagrams and even on RockAuto for the connectors that would be normally located on the door harness so that I can wire my own harness (keeping in mind that my truck does not have power mirrors at all in it's stock configuration), but everything states that there should be four wires for the directional movement of the motors, and two more wires for the heating element.

The mirrors only have five wires i the connector, whereas the diagrams show there should be six. On top of that, based on the diagrams, onn the passenger side there are two wires that tire into each other that are not tied together on the driver's side. At first I thought I was looking at a picture of the passenger side mirror connector and that the aftermarket manufacturer tied these wires together inside the harness or something, but that wasn't the case because both connectors have only five wires.

I've attached a picture of the mirror connector in my original post (I don't want to waste space by uploading them again). Here are links to the diagrams in PDF (too big to upload, had to put them on my web server):

http://www.connectedperformancepc.com/Downloads/Power-Mirror-Switch.pdf
http://www.connectedperformancepc.com/Downloads/Power-Mirror-Wiring.pdf
http://www.connectedperformancepc.com/Downloads/Power-Mirror-Circuit.df

Can anyone shed some light on this?

[DmaxMaverick]

It's possible that "plug and play for 99-02" doesn't mean what you think it means. This was a "transition year" for GM trucks, meaning, only the 1500 and 2500LD trucks were "updated" to GMT-800 tooling, with no option for a 2500HD or 3500 until 2001 M/Y. "Plug and Play", then, would only be that for 1999 and 2000 1500 and 2500LD trucks. The electrical systems were updated, again, in 2003, all models (to a multiplexed system), so many previous year electrical components were not easily adapted, and many 2003+ components were not easily backward-compatible.

Ultimately, you are attempting to adapt a GMT-800 component to a GMT-400 truck. It's no surprise the connectors don't match, and/or wire harnesses aren't present. GMT-800 trucks used only one harness (for each model series), regardless of the selected RPO's, so even if an option wasn't selected (such as power and/or heated mirrors), the harness and connectors were still present. For example, my 2001 2500HD was delivered with only power mirrors (no heat), and no rear defog. I later updated the system to power/heated mirrors and rear defog. I only had to upgrade the HVAC head to the "rear defog" option, and plug in power/heated mirrors and rear defog glass (replaced after an incident), to the existing wire harness connectors. I have since also done the same on trucks w/o power mirrors (the connectors were present, but not connected to anything), but they also required adding the OEM power mirror control. No additional wiring or programming was required. I've also done the same with the fog lamps, roof-top beacon and clearance lamps.

In your case, it should be a simple (or not so simple) matter of updating your HVAC head to the rear defog model and power mirror control, and splicing into the BCM harness as necessary. The BCM should not need reprogramming once all the components and controls are present.

I think what you need is the 99-02 GMT-800 connector pin-outs for the mirrors (and rear defog) and controls. I have them, and will look up what I think you'll need.

[DmaxMaverick]

Check your email. Diagrams attached.

It seems the mirror and rear defog circuits are not BCM controlled. They are timed and relayed through the HVAC control module, for the model years in question. 2003+ models are very different, so try not to confuse them into the mix.