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Home >> Chevrolet >> 2005 >> Impala Police >> 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: Exterior Lights Schematics 
Connector End View Reference: Master Electrical Component List in Wiring Systems
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the headlamp switch.
  3. Turn ON and OFF the headlamp high beam switch.
  4. Turn OFF the headlamp switch.
  5. Turn OFF the ignition.
Do the headlamps operate properly?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3
  1. Turn OFF the ignition.
  2. Disconnect the headlamp relay.
  3. Turn ON the ignition, with the engine OFF.
Do the headlamps turn OFF?
Go to Step 4  Go to Step 9 
4
  1. Turn OFF the ignition.
  2. Reconnect the headlamp relay.
  3. Disconnect the headlamp switch.
  4. Turn ON the ignition, with the engine OFF.
Do the headlamps turn OFF?
Go to Step 20  Go to Step 5 
5
  1. Turn OFF the ignition.
  2. Disconnect the body control module (BCM) connector C2.
  3. Turn ON the ignition with the engine OFF.
Do the headlamps turn OFF?
Go to Step 7  Go to Step 6 
6
  1. Turn OFF the ignition.
  2. Disconnect the BCM connector C1.
  3. Turn ON the ignition with the engine OFF.
Do the headlamps turn OFF?
Go to Step 21  Go to Step 8 
7 Test the headlamp switch signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and repair a short to ground in the headlamp switch signal circuit?
Go to Step 22  Go to Step 21 
8 Test the headlamp relay control circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and repair a short to ground in the headlamp switch signal circuit?
Go to Step 22  Go to Step 19 
9 Disconnect the turn signal/multifunction switch.
Do the headlamps turn OFF?
Go to Step 10  Go to Step 11 
10 Test for a short to ground in the headlamp relay switch supply circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 22  Go to Step 16 
11 Are the high beam headlamps always ON? Go to Step 12  Go to Step 13 
12 Repair a short to ground in the headlamp high beam signal circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you complete the repair?
Go to Step 22  -
13
  1. Install the headlamp relay.
  2. Connect the turn signal/multifunction switch.
  3. Remove the DRL relay.
Do the low beam headlamps turn OFF?
Go to Step 14  Go to Step 18 
14 Using a test lamp connected to the DRL relay voltage supply circuit, probe the DRL relay control circuit.
Does the test lamp illuminate?
Go to Step 15  Go to Step 17 
15 Test for a short to ground in the DRL relay control circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 22  -
16 Replace the turn signal/multifunction switch. Refer to Multifunction, Turn Signal Switch Replacement in Steering Wheel and Column.
Did you complete the replacement?
Go to Step 22  -
17 Replace the DRL relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems.
Did you complete the replacement?
Go to Step 22  -
18 Repair a short to ground in the low beam switched ground circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you complete the repair?
Go to Step 22  -
19 Replace the headlamp relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems.
Did you complete the replacement?
Go to Step 13  -
20 Replace the headlamp switch. Refer to Headlamp Switch Replacement  in Steering Wheel and Column.
Did you complete the replacement?
Go to Step 22  -
21 Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?
Go to Step 22  -
22 Connect all components and connectors then operate the system in order to verify the repair.
Did you correct the condition?
System OK Go to Step 2