DTC B1078: Daytime Running Lights Signal Error 1.
Clear the DTCs using the HDS.
2.
Cycle the ignition switch to OFF, and then back ON.
3.
Operate the parking brake lever.
4.
Check for DTCs using the HDS.
Is DTC B1078 indicated?
YES - Go to step 5.
NO - Intermittent failure, the daytime running lights system is OK at this time. Check pinfits and connections.
5.
Turn the headlight switch ON, then push the combination light switch forward for high beams.
Do both headlights come on?
YES - Go to step 6.
NO - Go to step 9.
6.
Turn the headlight switch OFF.
7.
Select LIGHTING SYSTEM from the HDS, and enter the DATA LIST.
8.
Check the ON/OFF information of the DRL Relay Command (Canada models) in the DATA LIST.
Is the information indicator ON?
YES - Replace the daytime running lights relay.
NO - Go to the relay control module input test.
Relay Control Module Input Test 9.
Check the No. 3
(10 A) or No. 5
(10 A) fuses in the under-hood fuse/relay box.
Are both fuses OK?
YES - Go to step 10.
NO - Replace the blown fuse and recheck the system.
10.
Check the headlight bulbs.
Are both bulbs OK?
YES - Go to step 11.
NO - Replace the blown bulb and recheck the system.
11.
Check for continuity between the No. 3 terminal of the headlight (high beam) 3P connectors and the No. 8 (left headlight) or No. 10 (right headlight) terminals of under-hood fuse/relay box 14P connector H.
Is there continuity?
YES - Go to step 12.
NO - Repair an open in the WHT/YEL (left headlight) or WHT/GRN (right headlight) wire.
12.
Check for continuity between the No. 2 terminal of the headlight (high beam) 3P connectors and body ground.
Is there continuity?
YES - Faulty relay control module; replace the under-hood fuse/relay box.
NO - Check the daytime running lights relay (left headlight). If OK, repair an open in the BLK and RED/BLK wire or poor ground (G201, G301).
