Test No 1: Stoplight Switch Circuit
- If stoplights do not operate, repair stoplight circuit. If stoplights operate, check stoplight switch input signal circuit. See INPUT SIGNAL CIRCUITS . If input signal circuit is okay, perform next procedure listed in DIAGNOSIS BY SYMPTOM table under TROUBLE SHOOTING.
- If input signal circuit is faulty, remove cruise control ECU, leaving electrical connector attached. Turn ignition on. Measure voltage between ground and terminal No. 2 (Green/White wire). See Figure. With brake pedal pressed, battery voltage should be present at terminal No. 2. With brake pedal released, battery voltage should be present at terminal No. 2.
- If voltage is as specified, perform next procedure listed in DIAGNOSIS BY SYMPTOM table under TROUBLE SHOOTING. If voltage is not as specified, check for faulty circuits between cruise control ECU and stoplight switch. Repair circuit(s) if necessary. If circuits are okay, replace cruise control ECU.