Stop Lamps Always On

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System.
1	Did you perform the Lighting Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - Lighting Systems
2	Depress the brake pedal. Does the system operate normally?	Go to Testing for Electrical Intermittents in Wiring Systems	Go to Step 3
3	Disconnect the stop lamp switch. Do the brake lamps go out?	Go to Step 6	Go to Step 4
4	Remove the CHMSL fuse. Do the brake lamps go out?	Go to Step 7	Go to Step 5
5	Remove the STOP fuse. Do the brake lamps go out?	Go to Step 8	Go to Step 9
6	Inspect for poor connections at the harness connector of the 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 11	Go to Step 10
7	Repair the short to voltage in the CHMSL supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 11	-
8	Repair the short to voltage in the stop lamp switch signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 11	-
9	Repair the short to voltage in the stop lamp supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 11	-
10	Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement?	Go to Step 11	-
11	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3