GM Service Manual Online
For 1990-2009 cars only

Stop Lamps Always On Pickup

Step

Action

Value(s)

Yes

No

DEFINITION: This diagnostic is only to be performed when the rear stoplamps remain illuminated at all times.

1

Was the Exterior Lights System Check performed?

--

Go to Step 2

Go to Exterior Lights System Check

2

Remove the Brake Lamp Relay.

Do the brake lights go out?

--

Go to Step 3

Go to Step 8

3

Measure voltage at D& of the Brake Lamp Relay Connector.

Was voltage present?

V

Go to Step 4

Go to Step 5

4

Disconnnect the Stoplamp, TCC, and Cruise Control Switch Connector.

Is voltage still present at D7 of the Brake Lamp Relay Connector?

V

Go to Step 6

Go to Step 7

5

Replace the Brake Lamp Relay.

Is the repair complete?

--

Go to Exterior Lights System Check

--

6

Repair the short to voltage in CKT 17 (WHT). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Exterior Lights System Check

--

7

Replace the Stoplamp, TCC, and Cruise Control Switch.

Is the repair complete?

--

Go to Exterior Lights System Check

--

8

Repair the short to voltage in CKT 20 (LT BLU). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Exterior Lights System Check

--

Stop Lamps Always On Suburban/Utility

Step

Action

Value(s)

Yes

No

DEFINITION: This diagnostic procedure should only be used when the rear stop lamps both stay illuminated at all times.

1

Was the Exterior Lights System Check performed?

--

Go to Step 2

Go to Exterior Lights System Check

2

Disconnect the Stop, TCC, and Cruise Control Switch.

Do the lamps turn off?

--

Go to Step 3

Go to Step 4

3

Replace the Stop, TCC, and Cruise Control Switch.

Is the repair complete?

--

Go to Exterior Lights System Check

--

4

Disconnect the Directional Signal Switch.

Do the lamps turn off?

--

Go to Step 5

Go to Step 8

5

Measure voltage at pin A1 of the Directional Signal Switch.

Is voltage present?

--

Go to Step 6

Go to Step 8

6

Repair the short to voltage on CKT 17 (WHT). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Exterior Lights System Check

--

7

Replace the Directional Signal Switch.

Is the repair complete?

--

Go to Exterior Lights System Check

--

8

Repair the short to voltage on CKT 18 (YEL) and CKT 19 (DK GRN). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Exterior Lights System Check

--