Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
	▶ Check for poor connection between PCM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Ignition "OFF".

Disconnect Stop Lamp Switch.

Measure voltage between Brake Light Switch terminal and chassis ground.

Measure voltage between Brake Test Switch terminal and chassis ground.

Ignition "ON".

Measure voltage between Brake Light Switch terminal and chassis ground.

Measure voltage between Brake Test Switch terminal and chassis ground.

Is voltage within the specifiation?

	▶ Go to next procedure.
	▶ Check fuse between battery and Stop Lamp Switch. Check for Open or Short in power circuit. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Ignition "OFF".

Disconnect Stop Lamp Switch and PCM harness connector.

Measure resistance between both ends of Brake Lamp Switch line.

Measure resistance between both ends of Brake Test Switch line.

Measure resistance between Brake Light Switch terminal of Switch harness connector and chassis ground.

Measure resistance between Brake Test Switch terminal of Switch harness connector and chassis ground.

Is resistance within specification?

	▶ Go to next procedure.
	▶ In case of No.3 : Repair Open in signal circuit and go to "Verification of Vehicle Repair" procedure. ▶ In case of No.4 : Repair Short in signal circuit and go to "Verification of Vehicle Repair" procedure.