For 1990-2009 cars only
- Inspect the circuit breaker to determine if it is open. Locate and repair the cause of the circuit overload if it is open and then replace the circuit breaker.
- Inspect ground and make certain that it is clean and tight.
- Inspect the lamp filaments to make certain that they are not open. Replace the lamp if any is found to be defective.
- Inspect for a broken (or partially broken) conductor inside the insulation which could cause a malfunction but prove good in a system test for continuity or voltage. These circuits may be intermittent or resistive, when loaded, and if possible, should be monitored for a voltage drop when the system is placed under load.
- Inspect for proper installation of aftermarket electronic equipment which might affect the operation of other equipment.
