Windshield Wiper Test 13A - Rear Wiper MUX Circuit Error

NOTE: Perform WINDSHIELD WIPER TEST 1A before proceeding with this test. For connector terminal identification and wiring diagrams, see appropriate sections in this article. Perform VERIFICATION TEST VER-1A after each repair.

CAUTION: Always turn ignition switch to OFF position prior to disconnecting or connecting any module connector.

Erase trouble code. Turn ignition on. Operate rear wiper for one minute (minimum). Using scan tool read Diagnostic Trouble Codes (DTCs). If rear wiper MUX circuit error code is present, go to next step. If code is not present, system is currently functioning correctly.
Disconnect Heater, Ventilation and Air Conditioning (HVAC) control module 21-pin Blue connector. Using scan tool in ohmmeter mode, measure resistance on HVAC connector, terminal No. 21 (Black/Light Green wire). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open Black/Light Green wire.
Using scan tool, monitor rear wiper switch voltage. If scan tool displays 5 volts, repair Yellow/White wire between Body Control Module (BCM) terminal No. 38 and HVAC Blue connector, terminal No. 2 for short to battery voltage. If scan tool does not display 5 volts, replace BCM. BCM is located with junction block. See Figure in CHIME TEST 2A.