Help Please!!! Troubleshooting Error Codes & Wiring

[BoostedCivic]

Hello,

I'm working on a friend's 1999 STS. I read articles on how to obtain the codes. It said to hold up and on/off for 3 seconds. That worked but they say that's how you do it on a 2000 not a 1999?? Regardless, the passenger front door doesn't work at all(windows and locks). The error codes I'm getting are....

IPC -- Instrument Panel Cluster
U1255 - Class 2 Communication Malfunction (Serial Data Line Malfunction)

DDM -- Drivers Door Module
U1161 - Loss of PDM Serial Data

And the Cadillac dealership said one of the wires was shorted. I can't remember if it was + or -.

I was wondering if anyone had the wiring diagram for the door module. I do car audio work so I'll be able to find the short, I just don't know what wires are what.

Thanks,
BoostedCivic