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Home >> Buick >> 2007 >> Lucerne CX >> Repair and Diagnosis >> Accessories & Equipment >> Interior/Illumination Lights >> Lighting Systems >> Diagnostic Information and Procedures >> Headlamps Always On - Low or High Beam

Headlamps Always On - Low or High Beam

Headlamps Always On - Low or High Beam

Step Action Yes No
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics 
Connector End View Reference: Master Electrical Component List
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2 Turn the headlamp switch to the OFF position.
Do the low and high beam headlamps remain OFF?
Go to Testing for Intermittent Conditions and Poor Connections Go to Step 3 
3 Remove the appropriate component either the headlamp module for low beams or HI BEAM relay for high beams.
Do the lamps turn OFF?
Go to Step 5  Go to Step 4 
4 Repair a short to battery positive voltage in the supply circuit of the affected headlamps. Refer to Wiring Repairs .
Did you complete the repair?
Go to Step 13  -
5
  1. Reinstall the appropriate component.
  2. Disconnect the lamp switch assembly.
Do the headlamps turn OFF?
Go to Step 12  Go to Step 6 
6 Are the high beam headlamps on at all times? Go to Step 7  Go to Step 8 
7 Test for a short to ground in FTP circuit and the headlamp dimmer switch high beam signal circuit. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
Go to Step 13  Go to Step 9 
8 Test for a short to ground in the headlamp switch ON signal circuit. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
Go to Step 13  Go to Step 9 
9 Disconnect the body control module (BCM) connector C1.
Do the headlamps turn OFF?
Go to Step 14  Go to Step 10 
10 Test for a short to ground in the affected low or high beam relay control circuit. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
Go to Step 14  Go to Step 11 
11 Replace the appropriate headlamp module or HI BEAM relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) .
Did you complete the replacement?
Go to Step 14  -
12 Replace the lamp switch assembly. Refer to Headlamp Switch Replacement .
Did you complete the replacement?
Go to Step 14  -
13 Replace the BCM. Refer to Control Module References for replacement, setup and programming.
Did you complete the replacement?
Go to Step 14  -
14 Operate the system in order to verify the repair.
Did you correct the condition?
System OK Go to Step 3