Cruise Control On-Off (Main) Switch Circuit

Remove the cruise control ECU with connector connected. See Figure. Turn ignition switch to ON position. Backprobing connector, measure voltage between ground and cruise control ECU connector terminal No. 11 (White/Blue wire). With cruise control main switch off, battery voltage should be present. With cruise control main switch on, voltage should be less than .5 volt. If voltage is not as specified, go to next step. If voltage is as specified, no problem is indicated at this time. Fault may be intermittent. If sent here from SYMPTOM DIAGNOSIS, perform next test listed.
Turn ignition switch to OFF position. Disable air bag system. See AIR BAG RESTRAINT SYSTEM article. Remove steering wheel center pad (air bag module). Disconnect cruise control switch 6-pin connector. Check for continuity between cruise control switch terminals No. 3 (White/Black wire) and No. 5 (White/Blue wire). No continuity should be present with cruise control switch in OFF position. Continuity should be present with cruise control switch held in ON position. If continuity is as specified, go to next step. If continuity is not as specified, replace cruise control switch and retest system.
Check wiring harness and connectors between cruise control ECU, cruise control switch and ground. Repair as necessary and retest system. If wiring harness and connectors are okay, replace cruise control ECU and retest system.