GM Service Manual Online
For 1990-2009 cars only

Backup Lamps Always On

Step

Action

Value(s)

Yes

No

1

Were you sent here from the Backup Lamps Diagnostic System Check?

--

Go to Step 2

Go to Backup Lamp System Check

2

Perform the BCM Diagnostic System Check

Refer to Diagnostic System Check - Body Control System .

Are any DTCs stored in memory?

--

Go to applicable table

Go to Step 3

3

Disconnect the back up lamp (manual) switch or the park neutral position (auto) switch connector.

Do the back up lamps turn OFF?

--

Go to Step 6

Go to Step 4

4

Remove the PERIM LP Micro Relay #38 from the underhood electrical center.

Do the back up lamps turn OFF?

--

Go to Step 5

Go to Step 7

5

  1. Leave the back up lamp (manual) switch or the park neutral position (auto) switch disconnected.
  2. Leave the PERIM LP Micro Relay #38 disconnected.
  3. Connect a DMM between the back up lamp (manual) switch connector terminal B or the park neutral position (auto) switch connector terminal F and ground.
  4. Measure for voltage on CKT 1524.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 9

Go to Step 8

6

Replace the back up lamp (manual) switch or the park neutral position (auto) switch.

Refer to Backup Lamp Switch Replacement Park/Neutral Position Switch Replacement .

Is the repair complete?

--

Go to Backup Lamp System Check

--

7

Repair the short to battery power in CKT 24.

Is the repair complete?

--

Go to Backup Lamp System Check

--

8

  1. Leave the PERIM LP Micro Relay #38 disconnected.
  2. Connect a DMM between ground and the CKT 38 terminal in the underhood electrical center which is used for the PERIM LP Micro Relay #38.
  3. Measure for continuity to ground on CKT 38.

Is CKT 38 continuous to ground?

--

Go to Step 11

Go to Step 10

9

Repair the short to battery power in CKT 1524.

Is the repair complete?

--

Go to Backup Lamp System Check

--

10

Replace the PERIM LP Micro Relay #38.

Is the repair complete?

--

Go to Backup Lamp System Check

--

11

  1. Disconnect the BCM connector C2.
  2. DMM still connected between ground and the CKT 38 terminal in the underhood electrical center which is used for the PERIM LP Micro Relay #38.

Is CKT 38 still continuous to ground?

--

Go to Step 12

Go to Step 13

12

Repair a short to ground in CKT 38.

Is the repair complete?

--

Go to Backup Lamp System Check

--

13

Replace the BCM.

Refer to Body Control Module Replacement Body Control Module (BCM) Programming/RPO Configuration .

Is the repair complete?

--

Go to Backup Lamp System Check

--