For 1990-2009 cars

1. Visually inspect the door lock fuse.
2. Verify that ground G201 is clean and tight.
3. Inspect for mechanical binds in the door lock system if the following conditions occur:

• | One or more of the door lock motors do not operate properly.

• | The other door lock motors function normally.

4. If a motor's internal circuit breaker trips, the circuit breaker will not reset until the voltage is removed from the motor.
5. Refer to Remote Keyless Entry System Check in Keyless Entry if the following conditions occur:

• | The left front door lock is the only inoperative lock.

• | The vehicle is equipped with keyless entry.

6. Refer to repair procedures in order to access the power door lock system.
7. Inspect for a broken (or partially broken) wire inside of the insulation.

A broken wire inside of the insulation may cause a system failure but prove good in a continuity/voltage test.

8. Inspect for proper installation of the aftermarket electronic equipment.

Improper installation of aftermarket electronic equipment affects the integrity of other systems.