GM Service Manual Online
For 1990-2009 cars only

Combination Valve Circuit--Brake Lamp Inoperative

Step

Action

Value(s)

Yes

No

DEFINITION: Brake lamp does not light when combination valve is disconnected.

1

  1. Disconnect the switch wire from the combination valve.
  2. Connect a jumper wire from the switch wire to ground.
  3. Ignition "ON."

Does the brake lamp light?

--

System OK

Go to Step 2

2

Check the brake lamp bulb.

Is the brake lamp bulb OK?

--

Go to Step 3

Go to Step 4

3

  1. Repair the open. Refer to Repair Procedures in Electrical Diagnosis.
  2. Recheck the circuit.

Does the brake lamp light?

--

System OK

--

4

  1. Replace the brake lamp bulb.
  2. Recheck the circuit.

Does the brake lamp light?

--

System OK

--