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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1085 (Lighting Systems) >> Diagnostic Information and Procedures >> Fog Lamps Inoperative

Fog Lamps Inoperative

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.
Fog Lamps Inoperative

Step Action Yes No
Schematic Reference:  Fog Lights 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
  1. Turn the ignition to the ON position.
  2. Turn the headlamp switch to the PARK position.
  3. Place the fog lamp switch in the ON position.
Are the fog lamps ON?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3 Is only one fog lamp inoperative? Go to Step 4  Go to Step 6 
4
  1. Disconnect the inoperative fog lamp.
  2. 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 23 
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 19  Go to Step 24 
6
  1. Place the headlamp switch in the HEAD position.
  2. 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 17  Go to Step 8 
8
  1. Disconnect the fog lamp relay.
  2. Turn the ignition to the ON position.
  3. Connect a test lamp between the switch side supply of the fog lamp relay and a ground.
Does the test lamp illuminate?
Go to Step 9  Go to Step 21 
9
  1. Turn the headlamp switch to the PARK position.
  2. Place the headlamp dimmer switch in the low beam position.
  3. Connect a test lamp between the coil side supply of the fog lamp relay and a ground.
Does the test lamp illuminate?
Go to Step 10  Go to Step 21 
10
  1. With the fog lamp switch in the ON position.
  2. Connect a test lamp between the coil side supply of the fog lamp relay and the control circuit of the fog lamp relay.
Does the test lamp illuminate?
Go to Step 12  Go to Step 11 
11
  1. Disconnect the fog lamp switch connector.
  2. Connect a test lamp between the fog lamps enable circuit of the fog lamp switch and battery positive voltage.
Does the test lamp illuminate?
Go to Step 13  Go to Step 15 
12 Connect a fused jumper between the switch side supply of the fog lamp relay and the fog lamps supply voltage circuit of the fog lamp relay.
Do the fog lamps illuminate?
Go to Step 20  Go to Step 16 
13
  1. Connect a test lamp between the coil side supply of the fog lamp relay and the control circuit of the fog lamp relay.
  2. Connect a fused jumper between the fog lamps enable circuit and the fog lamp relay control circuit of the fog lamp switch.
Does the test lamp illuminate?
Go to Step 18  Go to Step 14 
14 Test for an open or high resistance in the control circuit of the fog lamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 30  Go to Step 21 
15 Test for an open, high resistance or short to battery positive voltage in the fog lamps enable circuit of the fog lamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 30  Go to Step 22 
16 Test for a open or high resistance 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 21 
17 Test for a short to ground in the fog lamp supply voltage circuit or the fog lamp indicator 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 21 
18 Inspect for poor connections at the harness connector of the fog lamp 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 30  Go to Step 26 
19 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 in Wiring Systems.
Did you find and correct the condition?
Go to Step 30  Go to Step 25 
20 Inspect for poor connections at the harness connector of the fog lamp 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 30  Go to Step 27 
21 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 in Wiring Systems.
Did you find and correct the condition?
Go to Step 30  Go to Step 28 
22 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 in Wiring Systems.
Did you find and correct the condition?
Go to Step 30  Go to Step 29 
23 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 in Wiring Systems.
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 in Wiring Systems.
Has the repair been made?
Go to Step 30  -
25 Replace the inoperative fog lamp. Refer to Fog Lamp Replacement - Front (Aztek)  or Fog Lamp Replacement - Front (Rendezvous) .
Has the repair been made?
Go to Step 30  -
26 Replace the fog lamp switch. Refer to Fog Lamp Switch Replacement - Front .
Has the repair been made?
Go to Step 30  -
27 Replace the fog lamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) in Wiring Systems.
Has the repair been made?
Go to Step 30  -
28 Replace the fuse block - underhood. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
Has the repair been made?
Go to Step 30  -
29
IMPORTANT: Perform the set up procedures for the Body Control Module (BCM). Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.
Replace the Body Control Module (BCM). Refer to Body Control Module Replacement in Body Control System.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