Diagnostic Test

1) GOOD TRIP INDICATED
Turn the ignition on.

With the scan tool, read DTC's.

Does the Good Trip Indicator display NO?

Yes
1. Go To 2).
No
1. Refer to the INTERMITTENT CONDITION diagnostic procedure.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
2) OPEN (B15) BRAKE SWITCH SIGNAL CIRCUIT

Fig 1: CHECKING BRAKE SWITCH SIGNAL CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition on.

Using a 12-volt test light connected to ground, back probe (B15) at the Stop Lamp Switch harness connector.

Does the test light illuminate brightly?

Yes
1. Go To 3).
No
1. Go To 4).
3) (B15) BRAKE SWITCH OPEN

Fig 2: CHECKING BRAKE SWITCH
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Stop Lamp Switch harness connector.

Test for continuity between pins 5 and 6 of the Stop Lamp Switch.

Is there continuity?

Yes
1. Repair the open in the (Z902) ground circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Replace the Stop Lamp Switch.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
4) (B15) BRAKE SWITCH SIGNAL CIRCUIT OPEN

Fig 3: CHECKING BRAKE SWITCH SIGNAL CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the PCM harness connector.

Test for continuity in circuit (B15) between the Stop Lamp Switch connector and the PCM connector.

Is there continuity?

Yes

Go To step 5).

No
1. Repair the open in the (B15) Brake Switch Signal circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
5) POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and Powertrain Control Module (PCM).

Look for any chafed, pierced, pinched, or partially broken wires.

Look for broken, bent, pushed out or corroded terminals.

Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes
1. Repair as necessary.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No

Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .