Headlamps Inoperative - Low Beams

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems.
1	Did you perform the Lighting System Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - Lighting Systems
2	Turn ON the headlamps. Ensure that the headlamp dimmer switch is in the LOW position. Do both low beam headlamps illuminate?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Is only one low beam headlamp inoperative?	Go to Step 11	Go to Step 4
4	Leave the headlamp switch in the HEAD position. Disconnect the headlamp dimmer switch. Connect a fused jumper between the low beam relay control circuit and the headlamp relay control circuit of the headlamp dimmer switch. Do the low beams illuminate?	Go to Step 8	Go to Step 5
5	Test for a poor connection or an open in the low beam relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	Go to Step 6
6	Remove the low beam headlamp relay. Install a fused jumper across the battery positive voltage supply circuit and the switched low beam voltage supply circuit. Do the low beam headlamps illuminate?	Go to Step 9	Go to Step 7
7	Test for a short to ground in the switched low beam voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	Go to Step 10
8	Inspect for a poor connection at the harness connector of the headlamp dimmer switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	Go to Step 12
9	Inspect for a poor connection at the low beam relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	Go to Step 13
10	Inspect for a poor connection at the harness connector of the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	Go to Step 15
11	Inspect the inoperative low beam headlamp power supply and ground circuit for a high resistance, short to ground, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	Go to Step 14
12	Replace the headlamp dimmer switch. Refer to Multifunction, Turn Signal Switch Replacement in Steering Wheel and Column. Did you complete the replacement?	Go to Step 16	-
13	Replace the low beam relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) in Wiring Systems. Did you complete the replacement?	Go to Step 16	-
14	Replace the inoperative low beam headlamp. Refer to Headlamp Assembly or Headlamp Bulb Replacement (Aztek) or Headlamp Assembly or Headlamp Bulb Replacement (Rendezvous) . Did you complete the replacement?	Go to Step 16	-
15	Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems Did you complete the replacement?	Go to Step 16	-
16	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3