STEP 1. Using scan tool MB991958, check for diagnostic trouble code.
Check if an A/C control panel DTC is set.(1) Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III) ." (2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Refer to DIAGNOSTIC TROUBLE CODE CHART . Go to Step 2.
STEP 2. Check mode selection damper control motor connector C-206 and A/C control panel connector C-232 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
STEP 3. Check the wiring harness between A/C control panel connector C-232 (terminals No.28, 21, 23, 22 and 24) and mode selection damper control motor connector C-206 (terminals No.3, 6, 2, 5 and 1).