Fog Lamps Inoperative

WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
Schematic Reference: Fog Lights Schematics Connector End View Reference: Power and Grounding Connector End Views .
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	Turn the ignition to the ON position. Turn the headlamp switch to the PARK position. Place the fog lamp switch in the ON position. Are both of the fog lamps ON?	Go to Testing for Intermittent Conditions and Poor Connections	Go to Step 3
3	Is only one fog lamp inoperative?	Go to Step 4	Go to Step 6
4	Disconnect the inoperative fog lamp. Using a test lamp connected to ground, probe the fog lamps supply voltage circuit of the inoperative fog lamp. Does the test lamp illuminate?	Go to Step 5	Go to Step 22
5	Using a test lamp, probe between the ground circuit and supply voltage circuit of the inoperative fog lamp. Does the test lamp illuminate?	Go to Step 18	Go to Step 24
6	Place the headlamp switch in the HEAD position. Place the headlamp dimmer switch in the HIGH beam position. Do the high beam headlamps operate properly?	Go to Step 7	Go to Headlamps Inoperative - High Beams
7	Check the FOG LP fuse for an open. Is the FOG LP fuse open?	Go to Step 16	Go to Step 8
8	Disconnect the FOG LP relay. Turn the ignition to the ON position. Connect a test lamp between the switch side supply of the FOG LP relay and a ground. Does the test lamp illuminate?	Go to Step 9	Go to Step 20
9	Turn the headlamp switch to the PARK position. Place the headlamp dimmer switch in the LOW beam position. Connect a test lamp between the coil side supply of the FOG LP relay and a ground. Does the test lamp illuminate?	Go to Step 10	Go to Step 20
10	Place the fog lamp switch in the ON position. Connect a test lamp between the coil side supply of the FOG LP relay and the control circuit of the FOG LP relay. Does the test lamp illuminate?	Go to Step 12	Go to Step 11
11	Disconnect the lamp switch assembly connector. Connect a jumper between the fog lamp switch signal circuit of the fog lamp switch and ground circuit. Do the fog lamps illuminate?	Go to Step 17	Go to Step 13
12	Connect a fused jumper between the switch side supply of the FOG LP relay and the fog lamps supply voltage circuit of the fog lamp relay. Do the fog lamps illuminate?	Go to Step 19	Go to Step 16
13	Connect a fused jumper between the fog lamp switch signal circuit and ground. Do the fog lamps illuminate?	Go to Step 23	Go to Step 14
14	Test for an open high resistance short to battery positive voltage or a short to ground in the fog lamps switch signal circuit of the fog lamp switch. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 30	Go to Step 15
15	Test for an open, high resistance or short to battery positive voltage in the control circuit of the FOG LP relay. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 30	Go to Step 21
16	Test for a short to ground in the fog lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 30	Go to Step 20
17	Inspect for poor connections at the harness connector of the lamp switch assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 30	Go to Step 26
18	Inspect for poor connections at the harness connector of the inoperative fog lamp. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 30	Go to Step 25
19	Inspect for poor connections at the harness connector of the FOG LP relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 30	Go to Step 27
20	Inspect for poor connections at the harness connector of the fuse block - underhood. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 30	Go to Step 28
21	Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 30	Go to Step 29
22	Repair an open or high resistance in the fog lamp supply voltage circuit of the inoperative fog lamp. Refer to Circuit Testing and Wiring Repairs . Has the repair been made?	Go to Step 30	-
23	Repair a poor connection or an open in the ground circuit of the fog lamp switch. Refer to Circuit Testing and Wiring Repairs . Has the repair been made?	Go to Step 30	-
24	Repair an open or high resistance in the ground circuit of the inoperative fog lamp. Refer to Circuit Testing and Wiring Repairs . Has the repair been made?	Go to Step 30	-
25	Replace the inoperative fog lamp. Refer to Headlamp, Fog Lamp, Turn Signal Lamp, Side Marker Lamp Replacement - Front . Has the repair been made?	Go to Step 30	-
26	Replace the lamp switch assembly. Refer to Headlamp Switch Replacement . Has the repair been made?	Go to Step 30	-
27	Replace the FOG LP relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) . Has the repair been made?	Go to Step 30	-
28	Replace the fuse block - underhood. Refer to Underhood Electrical Center or Junction Block Replacement . Has the repair been made?	Go to Step 30	-
29	Replace the BCM. Refer to Control Module References for replacement, setup and programming. Has the repair been made?	Go to Step 30	-
30	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2