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Procedure H, Stoplight Switch Circuit

  1. Stoplight Fuse:  Ensure ignition is off. Check stoplight fuse. Replace fuse if blown. If fuse blows after replacing, check wiring harness for a short circuit between fuse and cruise control ECU terminal No. 17 or stoplight switch terminal No. 1. See Figure or Figure . If fuse is okay, go to next step.
  2. Stoplight Switch:  Disconnect stoplight switch. Check continuity between wiring harness side of stoplight switch terminal No. 3 and ground. See Figure. If continuity exists, go to next step. If no continuity exists, repair open circuit in wire harness between stoplight switch terminal No. 3 and ground. Also check for faulty ground.
  3. Check stoplight switch operation. Refer to STOPLIGHT SWITCH TEST  under TESTING. If switch is faulty, replace switch and recheck cruise control system. If switch is okay, reconnect stoplight switch and go to next step.
  4. Cruise Control ECU:  Disconnect ECU. Check for battery voltage between wiring harness side of ECU terminal No. 17 and ground with brake pedal released. See Figure. If voltage is correct, go to next step. If voltage is incorrect, repair open circuit in wire harness between ECU terminal No. 17 and stoplight fuse.
  5. Check for battery voltage between wiring harness side of ECU terminal No. 18 and ground with brake pedal depressed. If voltage is correct, replace faulty ECU and recheck cruise control system. If voltage is incorrect, repair in wire harness open circuit between ECU terminal No. 18 and stoplight switch terminal No. 3.
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