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

Rear Fog Lamps Always On

Step

Action

Value(s)

Yes

No

1

Were you sent here 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 foglamp operation?

--

Go to the applicable DTC table

Go to Step 3

3

Remove the RR FOG LP Micro Relay #37.

Are the rear fog lamps still ON?

--

Go to Step 4

Go to Step 7

4
  1. Disconnect the underhood electrical center connectors C2 and C3.
  2. Connect a DMM between:
    3. • the underhood electrical center connector C2 terminal E4 and ground.
    • the underhood electrical center connector C3 terminal F1 and ground.
  3. Check for any present voltage on CKT 122 at these two locations.

Is voltage present on CKT 122 during either of these tests?

--

Go to Step 5

Go to Step 6

5

Repair the short to battery voltage in CKT 122 at either of the two locations as listed in step four.

Is the repair complete?

--

Go to Foglamp System Check

--

6

Replace the underhood electrical center.

Is the repair complete?

--

Go to Foglamp System Check

--

7
  1. Disconnect the body control module (BCM) connector C1.
  2. Connect a DMM between the BCM connector C1 terminal B3 and ground.
  3. Measure the CKT 1901 for continuity between the BCM connector C1 terminal B3 and ground.

Is CKT 1901 continuous between these two terminals?

--

Go to Step 8

Go to Step 9

8

Repair the short to ground in CKT 1901.

Is the repair complete?

--

Go to Foglamp System Check

--

9
  1. Reconnect the underhood electrical center connectors C2 and C3.
  2. BCM connector C1 still disconnected.
  3. Reinstall the RR FOG LP Micro Relay #37 into the underhood electrical center.

Are the fog lamps ON?

--

Go to Step 10

Go to Step 11

10

Replace the RR FOG LP Micro Relay #37.

Is the repair complete?

--

Go to Foglamp System Check

--

11
  1. Disconnect the BCM connector C2.
  2. Connect a DMM between the BCM connector C2 terminal D5 and ground
  3. Check for voltage at the BCM connector C2 terminal D5.

Is voltage present on CKT 187 during this test?

--

Go to Step 12

Go to Step 13

12
  1. Disconnect the rear fog lamp switch connector.
  2. Connect the DMM between the BCM connector C2 terminal D5 and ground.
  3. Check for voltage at the BCM connector C2 terminal D5.

Is voltage present on CKT 187 during this test?

--

Go to Step 15

Go to Step 14

13

Replace the BCM.

Is the repair complete?

--

Go to Foglamp System Check

--

14

Replace the rear fog lamp switch.

Is the replacement complete?

--

Go to Foglamp System Check

--

15

Repair the short to battery power in CKT 187.

Is the repair complete?

--

Go to Foglamp System Check

--