Problem: The customer brought the vehicle in
because the power window, sunroof and mirrors were not working.
All three stopped working at the same time.
Details: The technician checked all of the
modules but found no diagnostic trouble codes (DTCs). Next he
used the scan tool to check for communication with the Body
Control Module (BCM) and driver door module (DDM). The BCM
communicated with the scan tool but the DDM would not. After
looking at the wiring diagram, the technician decided to check
the power and ground connections at the DDM.
Confirmed Repair: In this case, the technician
found the ignition switch signal wire (yellow wire on pin A25) to
the DDM was broken at the driver door connector (see image).
After repairing the wire, all of the components began working
Diagnostic Insight: You may wonder how this
ignition signal wire failure could have caused this problem. The
DDM senses the ignition status on that yellow wire and sends that
information through the network data line to the mirrors, sunroof
and windows. If the ignition signal is lost to the DDM, as in
this case, it can’t communicate that information to the other
modules in its network and those accessories don’t operate.