Test B (Rear Wiper Module)
- Disconnect rear wiper module. Turn ignition switch to RUN position. Move rear wiper/washer switch to WIPER position. Ensure tailgate is closed. On electrical connector to wiper module, measure voltage between terminal "A" (Orange/Black wire) and ground. See Fig 1
. If battery voltage is present, go to step 2). If battery voltage is not present, check Orange/Black wire (circuit No. 60) for open.
- Measure voltage between terminals "A" (Orange/Black) and "B" (Black) of electrical connector. If battery voltage is present, go to next step. If battery voltage is not present, check Black wire (circuit No. 150) and ground circuit for open.
- Measure voltage between terminal "C" (Gray/Black) on electrical connector and ground. If battery voltage is present, go to step 4). If battery voltage is not present, check tailgate lock switch and Gray and Gray/Black wires for open(s).
- Remove rear wiper module. See WIPER MOTOR
. Apply battery voltage to wiper module terminals "A" and "C". See Fig 1
. Ground terminal "B". Motor should run. If motor runs, go to step 5). If motor does not run, replace wiper motor.
- Apply battery voltage to terminal "C". Ground terminal "B". Motor should park. If motor does not park, replace wiper motor.
Courtesy of GENERAL MOTORS CORP.