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Procedure A, Power Source Circuit

  1. ECU-Ignition Fuse: Turn ignition switch on and check Electronic Control Unit-Ignition (ECU-IG) fuse. Replace fuse if blown. If fuse blows, check wiring harness for a short circuit to ground between fuse and cruise control switch terminal No. 3 (20-pin connector) or ECU terminal No. 1 (12-pin connector). See Figure. If fuse is okay, turn ignition off and go to next step.
  2. Cruise Control Switch: Disconnect cruise control switch. Check continuity between wiring harness side of cruise control switch terminal No. 17 (Brown wire) and ground. If continuity exists, go to next step. If no continuity exists, repair wiring harness open circuit between cruise control switch terminal No. 17 (Brown wire) and ground. Also check for faulty ground.
  3. Check cruise control switch for proper operation. See CRUISE CONTROL SWITCH TEST in this article. If switch is defective, replace switch and recheck cruise control system. If cruise control switch is okay, reconnect switch and go to next step.
  4. Cruise Control ECU: Disconnect electronic control unit. With MAIN cruise control switch on, check continuity between wiring harness side of ECU terminal No. 6 (White wire) and ground. If continuity exists, go to next step. If no continuity exists, repair wiring harness open circuit between ECU terminal No. 6 (White wire) and cruise control switch terminal No. 15 (White wire).
  5. Disconnect ECU. Check continuity between wiring harness side of ECU terminal No. 15 (Brown wire) and ground. If continuity exists, go to next step. If no continuity exists, check wiring harness for an open circuit between ECU terminal No. 15 (Brown wire) and ground. Also check for faulty ground.
  6. Check for battery voltage at wiring harness side of ECU terminal No. 12 (Red wire). If battery voltage is present, go to next step. If no voltage exists, repair wiring harness open circuit to ECU terminal No. 12 (Red wire).
  7. Check gauges fuse. Replace fuse if blown. If fuse blows, check wiring harness for a short circuit between fuse and ECU terminal No. 4 (Green/White wire). If fuse is okay, go to next step.
  8. Connect wiring harness side of ECU terminal No. 4 (Green/White wire) to ground. See Figure. Observe if cruise control indicator light comes on. If cruise control light comes on, replace faulty ECU and recheck cruise control system.
  9. If cruise control light does not come on, check indicator light bulb. Replace bulb if necessary. If bulb is okay, repair wiring harness open circuit between gauges fuse and ECU terminal No. 4 (Green/White wire).
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