GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Corvette 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Fog Lamps Inoperative - All

Fog Lamps Inoperative

Step

Action

Value(s)

Yes

No

1

Were you sent from the Foglamp System Check?

--

Go to Step 2

Go to Foglamp System Check

2

Perform the BCM Diagnostic System Check?

Are any DTCs stored in memory related to fog lamp operation?

--

Go to applicable diagnostic table

Go to Step 3

3
  1. Disconnect the LH fog lamp connector.
  2. Connect a DMM between the LH fog lamp connector terminal B and ground.
  3. Turn the ignition switch to the ON position.
  4. Turn the headlamps ON.
  5. Depress the foglamp switch button.
  6. Measure the voltage at the LH fog lamp connector terminal B.

Is the voltage within the specified value?

10.0-14.0V

Go to Step 28

Go to Step 4

4

Does the front fog lamp indicator illuminate?

--

Go to Step 27

Go to Step 5

5
  1. Remove the Fog LP Micro Relay #39.
  2. Connect a DMM between the underhood electrical center BAT terminal which is used for the Fog LP Micro Relay #39 (switch side) and ground.
  3. Measure the voltage at the underhood electrical center BAT terminal which is used for the Fog LP Micro Relay #39 (switch side).

Is the voltage within the specified value?

10.0-14.0V

Go to Step 6

Refer to Power Distribution

6

Check the FOG LP Minifuse® #6 for being open.

Is the FOG LP Minifuse® #6 open?

--

Go to Step 7

Go to Step 8

7

Repair the short to ground in CKT 34 between the underhood electrical center connector C2 terminal D1 and the fog lamp switch connector terminal 5 or the underhood electrical center connector C3 terminal C1/E4 and the LH/RH fog lamp (see schematic).

Is the repair complete?

--

Go to Foglamp System Check

--

8

Install a jumper wire between the BAT terminal and the CKT 34 terminal in the underhood electrical center which is used for the Fog LP Micro Relay #39 (switch side).

Do the fog lamps and the fog lamp indicator illuminate?

--

Go to Step 9

Go to Step 12

9
  1. Connect the DMM between the underhood electrical center BAT terminal which is used for the FOG LP Micro Relay #39 (coil side) and ground.
  2. Measure the voltage at the BAT terminal which is used for the FOG LP Micro Relay #39 (coil side).

Is the voltage within the specified values?

10.0-14.0V

Go to Step 10

Refer to Power Distribution

10
  1. Disconnect the BCM connector C1.
  2. Connect a DMM between the CKT 1317 terminal in the underhood electrical center (which is used for the FOG LP Micro Relay #39) and the BCM connector C1 terminal B4.
  3. Measure CKT 1317 for continuity between the underhood electrical center CKT 1317 terminal and the BCM connector C1 terminal B4.

Is CKT 1317 continuous between these two terminals?

--

Go to Step 13

Go to Step 11

11

Repair the open in CKT 1317.

Is the repair complete?

--

Go to Foglamp System Check

--

12

Repair the open in CKT 34 between:

    • the underhood electrical center connector C2 terminal D1 and the fog lamp switch connector terminal 5
    • the underhood electrical center connector C3 terminal C1 and the LH fog lamp.
    • the underhood electrical center connector C3 terminal E4 and the RH fog lamp.

Is the repair complete?

--

Go to Foglamp System Check

--

13
  1. Reinstall the FOG LP Micro Relay #39 into the underhood electrical center.
  2. Install a fused jumper (10 A) between the BCM connector C1 terminal B4 and ground.

Do the fog lamps and the fog lamp indicator illuminate?

--

Go to Step 15

Go to Step 14

14

Replace FOG LP Micro Relay #39.

Is the repair complete?

--

Go to Foglamp System Check

--

15
  1. Disconnect the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) connector.
  2. Connect a DMM between the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) connector terminal 1 and ground.
  3. Measure the voltage at the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) connector terminal 1.

Is the voltage within the specified value?

10.0-14.0V

Go to Step 22

Go to Step 16

16

Check the F/TNK DR Minifuse® #32 for an open.

Is the fuse open?

--

Go to Step 18

Go to Step 17

17
  1. Remove the F/TNK DR Minifuse® #32.
  2. Connect a DMM between the instrument panel electrical center terminal A (which is used for the F/TNK DR Minifuse® #32) and ground.
  3. Measure the voltage at instrument panel electrical center terminal A.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 19

Refer to Power Distribution

18
  1. Remove the F/TNK DR Minifuse® #32.
  2. Leave the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) still disconnected.
  3. Connect a DMM between the instrument panel electrical center terminal B (which is used for the F/TNK DR Minifuse® #32) and ground.
  4. Measure CKT 2840 for continuity to ground.

Is CKT 2840 shorted to ground?

--

Go to Step 20

Go to Step 21

19

Repair the open in CKT 2840.

Is the repair complete?

--

Go to Foglamp System Check

--

20

Repair the short to ground in CKT 2840.

Is the repair complete?

--

Go to Foglamp System Check

--

21

Repair the short to ground in CKT 192.

Is the repair complete?

--

Go to Foglamp System Check

--

22
  1. Disconnect the BCM Connector C2.
  2. Connect a DMM between the BCM connector C2 terminal D4 and the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) connector terminal 2.
  3. Measure CKT 192 for continuity the between the BCM connector C2 terminal D4 and the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) connector terminal 2.

Is CKT 192 continuous between these two terminals?

--

Go to Step 23

Go to Step 24

23
  1. Reconnect the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) connector.
  2. Connect a DMM between the BCM connector C2 terminal D4 and ground.
  3. Press the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) button.
  4. Measure the voltage at the BCM connector C2 terminal D4 with the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export) button depressed.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 25

Go to Step 26

24

Repair the open in CKT 192.

Is the repair complete?

--

Go to Foglamp System Check

--

25

Replace the BCM.

Is the repair complete?

--

Go to Foglamp System Check

--

26

Replace the fog lamp/rear compartment lid release switch (domestic) or the fog lamp switch (export).

Is the repair complete?

--

Go to Foglamp System Check

--

27
  1. Disconnect the LH/RH foglamp connectors.
  2. Connect a DMM between the LH/RH foglamp connector terminal B and:
    3. • the underhood electrical center connector C3 terminal C1.
    • the underhood electrical center connector C3 terminal E4
  3. Measure CKT 34 for continuity between the underhood electrical center connector C3 terminals C1/E4 and the LH/RH foglamp connectors.

Is CKT 34 continuous between these two terminals?

--

Go to Step 32

Go to Step 31

28
  1. Disconnect the LH/RH foglamp connectors.
  2. Connect a DMM between the LH/RH foglamp connector terminal A and ground.
  3. Measure CKT 150 for continuity between the LH/RH foglamp connector terminal A and ground.

Is CKT 150 continuous to ground?

--

Go to Step 30

Go to Step 29

29

Repair the open in CKT 150 between the foglamp connector and G102.

Is the repair complete?

--

Go to Foglamp System Check

--

30

Replace the inoperative foglamp bulb.

Is the repair complete?

--

Go to Foglamp System Check

--

31

Repair the open in CKT 34.

Is the repair complete?

--

Go to Foglamp System Check

--

32

Replace the underhood electrical center.

Is the repair complete?

--

Go to Foglamp System Check

--