Diagnostic Procedure

1. Apply brake pedal and view brakelights. Do brakelights illuminate? If so, go to step  7. If not, go to next step.
2. Measure the resistance in fuse No. 23 (15-amp). Is resistance of fuse 5 ohms or less? If so, go to step  4. If not, go to next step.
3. Disconnect Brake Pedal Position (BPP) switch. Measure the resistance between BPP switch harness connector terminal No. 2 and ground. See Fig 1. Is the resistance 10 ohms or less? If so, repair short to ground in Light Green/Red wire and test the system for normal operation. If not, go to next step.
4. Measure the resistance between output side of fuse No. 23 (15-amp) and BPP switch. See Fig 2. Is the resistance 5 ohms or less? If so, go to next step. If not, repair open in Light Green/Red wire and test the system for normal operation.
5. Measure resistance of BPP switch while open (OFF) and closed (ON). See Fig 3. Is resistance of switch greater than 10 ohms while OFF, and 5 ohms or less while ON? If so, go to next step. If not, replace BPP switch and test the system for normal operation. See BRAKE PEDAL POSITION SWITCH  under REMOVAL & INSTALLATION.
6. Disconnect shift interlock actuator harness connector. Measure resistance between shift interlock actuator harness connector terminal No. 2 and ground. See Fig 4. Is resistance 10 ohms or less? If so, repair short to ground and test the system for normal operation. If not, go to next step.
7. Measure resistance between shift interlock actuator harness connector terminal No. 2 and BPP switch harness connector terminal No. 1. See Fig 5. Is resistance 5 ohms or less? If so, go to next step. If not, repair open and test the system for normal operation.
8. Turn ignition switch to ON position. Measure voltage between shift interlock actuator harness connector terminal No. 3 and ground. See Fig 6. Is the voltage greater than 10 volts? If so, go to step  12. If not, go to next step.
9. Turn ignition switch to OFF position. Measure resistance in fuse No. 26 (7.5-amp). Is resistance of fuse 5 ohms or less? If so, go to step  11. If not, go to next step.
10. Measure resistance between shift interlock actuator harness connector terminal No. 3 and ground. See Fig 7. Is resistance 10 ohms or less? If so, repair short to ground in Gray/Yellow wire and test the system for normal operation. If not, go to next step.
11. Measure resistance between output side of fuse No. 26 (7.5-amp) and shift interlock actuator harness connector terminal No. 3. See Fig 8. Is resistance 5 ohms or less? If so, go to next step. If not, repair open in Gray/Yellow wire and test the system for normal operation.
12. Measure the resistance between ground and shift interlock actuator harness connector terminals No. 1 and 6. See Fig 9 and Fig 10 . Are the resistances less than 5 ohms? If so, shift interlock actuator is not serviceable separate from steering column. Replace steering column. See appropriate STEERING COLUMNS article in STEERING. After repairs, test the system for normal operation. If not, repair open in appropriate ground circuit and test the system for normal operation.