DTC B1075: Headlight Switch Back-up Circuit Malfunction

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK(0) and then back to ON (II).
Turn the headlight switch ON for 5 seconds and OFF.
Check for DTCs with the HDS.
Is DTC B1075 indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections.
Select LIGHTING from the BODY ELECTRICAL SYSTEM SELECT menu, and enter DATA LIST.
Check the ON/OFF information of the HEADLIGHT BACK-UP with the HDS.
Is OFF indicated?

YES -Go to step 7.

NO -Check for a short in the WHT wire between the combination switch control unit and the relay control module (H/L BACK-UP line) or between the combination switch control unit and the MICU, if the harness is OK, replace the combination switch control unit (see WIPER/WASHER SWITCH (COMBINATION SWITCH CONTROL UNIT) INPUT TEST ).
Turn the headlight switch ON.
Select LIGHTING from the BODY ELECTRICAL SYSTEM SELECT menu, and enter DATA LIST.
Check the ON/OFF information of the HEADLIGHT BACK-UP with the HDS.
Is ON indicated?

YES -Go to the relay control module input test (see RELAY CONTROL MODULE INPUT TEST ) and check for a poor ground, if the GND line is OK, replace the under-hood fuse/relay box (see DTC B1065: RELAY CONTROL MODULE LOST COMMUNICATION WITH DRIVER'S MPCS UNIT (DRLOCKSW MESSAGE) ).

NO -Check for an open in the wire between the combination switch control unit and the relay control module (H/L BACK-UP line) or between the combination switch control unit and the MICU, if the wire is OK, replace the combination switch control unit (see WIPER/WASHER SWITCH (COMBINATION SWITCH CONTROL UNIT) INPUT TEST ).