For 1990-2009 cars

The stop lamp switch indicates brake pedal status to the ABS control module (EBTCM). The normally open stop lamp switch interrupts voltage to the EBTCM. Applying brake pedal "closes" switch and supplies voltage on circuit 20 to the EBTCM.

### DTC Parameters

DTC C0165 will set if:

• | The EBTCM senses an open condition in the brake switch input, all brake lamps, or brake lamp grounds for 2 seconds.

• | Open brake switch circuit may result in possible false setting of wheel speed codes C0036, C0041, C0046, or C0051.

• | The wrench light will be turned On.

### Diagnostic Aids

• | It is very important to thoroughly inspect wiring components and connectors. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.

• | Inspect any circuitry that may be causing the complaint for the following conditions:

- | Backed out terminals

- | Improper mating

- | Broken connector locks

- | Improperly formed or damaged terminals

- | Poor terminal-to-wiring connections.

- | Physical damage to the wiring harness.

• | The following conditions may cause an intermittent malfunction:

- | A poor connection

- | Rubbed-through wire insulation

- | A broken wire inside the insulation

Possible causes for DTC C0165 to set:

• | Brake switch input circuit open.

• | All brake lamps open.

• | All brake lamp grounds open.

• | Internal EBTCM problems.