Headlamps Inoperative - Low Beams (Standard or w/TR7-TT6)

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 ignition, with the engine OFF. Turn ON the headlamp switch. Cycle the headlamp dimmer switch between the high beam and low beam positions. Turn OFF the headlamp switch. Turn OFF the ignition. Did the headlamps operate properly?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Install a scan tool. Turn ON the ignition, with the engine OFF. Turn ON the headlamps. With the scan tool, observe the Headlamp Switch parameter in the dash integration module (DIM) Inputs data list. Does the data parameter display ON?	Go to Step 4	Go to Step 5
4	Place the headlamp dimmer switch in the low beam position. With a scan tool, command the High/Low Beam Relay ON and OFF from the DIM Special Functions, Output Control data list. Did both of the low beam headlamps turn ON and OFF?	Go to Step 16	Go to Step 6
5	Turn OFF the ignition. Disconnect the multifunction, turn signal switch. Connect a 3-amp fused jumper between the headlamp switch headlamps ON signal circuit of the multifunction, turn signal switch and the ground circuit of the multifunction, turn signal switch. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Headlamp Switch parameter. Does the Headlamp Switch parameter display ON?	Go to Step 17	Go to Step 14
6	Turn OFF the ignition. Disconnect the headlamp low beam relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Connect a test lamp between the headlamp low beam relay control side supply voltage circuit and a good ground. Turn ON the low beam headlamps. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate?	Go to Step 7	Go to Step 12
7	Connect a test lamp between the headlamp low beam relay switch side supply voltage circuit and a good ground. Does the test lamp illuminate?	Go to Step 8	Go to Step 22
8	Turn OFF the ignition. Connect a test lamp between the headlamp low beam relay control circuit and the headlamp low beam relay control side supply voltage circuit. Turn ON the ignition, with the engine OFF. With a scan tool command the High/Low Beam relay ON and OFF. Did the test lamp turn ON and OFF with each command?	Go to Step 9	Go to Step 13
9	Turn OFF the ignition. Connect a 40-amp fused jumper between the headlamp low beam relay switch side supply voltage circuit and the headlamp low beam supply voltage circuit. Turn ON the ignition, with the engine OFF. Did both of the low beam headlamps illuminate?	Go to Step 18	Go to Step 10
10	Disconnect the inoperative low beam headlamp bulb. Connect a test lamp between the low beam headlamp supply voltage circuit of the inoperable low beam headlamp bulb and the ground circuit of the inoperable low beam headlamp bulb. Does the test lamp illuminate?	Go to Step 20	Go to Step 11
11	Test the headlamp low beam supply voltage circuit for a high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 27	Go to Step 21
12	Test the control side supply voltage circuit of the headlamp low beam relay for a high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 27	Go to Step 16
13	Test the headlamp low beam relay control circuit for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 27	Go to Step 16
14	Test the ground circuit of the multifunction, turn signal switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 27	Go to Step 15
15	Test the headlamp switch headlamps on signal circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 27	Go to Step 16
16	Test the twilight sentinel delay signal circuit of the DIM for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 27	Go to Step 19
17	Inspect for poor connections at the harness connector of the multifunction, turn signal 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 27	Go to Step 23
18	Inspect for poor connections at the headlamp 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 27	Go to Step 24
19	Inspect for poor connections at the harness connector of the DIM. 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 27	Go to Step 25
20	Inspect for poor connections at the harness connector of the inoperative headlamp bulb. 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 27	Go to Step 26
21	Repair the open or high resistance in the headlamp ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 27	-
22	Repair the high resistance or open in the switch side supply voltage circuit of the headlamp low beam relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 27	-
23	Replace the multifunction, turn signal switch. Refer to Multifunction, Turn Signal Switch Replacement in Steering Wheel and Column. Did you complete the replacement?	Go to Step 27	-
24	Replace the headlamp low beam 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 27	-
25	IMPORTANT: Perform the setup procedure for the DIM. Replace the DIM. Refer to Dash Integration Module Replacement in Body Control System.Did you complete the replacement?	Go to Step 27	-
26	Replace the inoperative headlamp bulb. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement . Did you complete the replacement?	Go to Step 27	-
27	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2