Test 10: Cruise Control Main Switch Circuit
WARNING: This page is about a different car, the 1997 Lexus SC 400. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
To avoid accidental air bag deployment, see AIR BAG RESTRAINT SYSTEM
article before removing or installing steering wheel pad.
- Remove cruise control ECU, but leave electrical connector(s) attached. Turn ignition on. Connect voltmeter between terminals no. 4 (+) and 13 (-) of cruise control ECU connector. See Figure.
- With main switch button released, battery voltage should be present. With main switch button pressed, less than 2 volts should be present. If voltage is as specified, perform next procedure listed in DIAGNOSIS BY SYMPTOM table under TROUBLE SHOOTING. If voltage is not as specified, go to next step.
- Remove steering wheel pad. Disconnect electrical connector from cruise control switch. Connect ohmmeter between terminals No. 3 and 5 of cruise control switch connector. See Figure. With main switch button released, there should be no continuity. With main switch button pressed, there should be continuity.
- If continuity is not as specified, replace cruise control switch. If continuity is as specified, check for faulty circuit between cruise control ECU and cruise control switch, and between cruise control switch and ground. Repair circuit if necessary. If circuit is okay, replace cruise control ECU.