Test 4: ASCD Brake/Stoplight Switch Check

Check Brake/Stoplight Switch Circuit

Turn ignition switch to LOCK position. Disconnect ASCD control unit harness connector. Turn ignition switch to RUN position. Turn ASCD MAIN switch on. Measure voltage between ground and terminal No. 5 (Green/Black wire) at ASCD control unit harness connector. See Figure . With brake pedal depressed, or with gear selector lever is in "P" or "N" position, zero volts should exist. With brake pedal released and gear selector in any position other than "P" or "N", battery voltage should exist. If readings are as specified, go to step 3 . If readings are not as specified, go to next step.
Check for a faulty ASCD brake switch or faulty Park Neutral Position (PNP) switch (A/T models). See SWITCHES under COMPONENT TESTS. Also check for a faulty ASCD hold relay, or open or short in wiring harness. See RELAYS under COMPONENT TESTS. See WIRING DIAGRAMS . Repair as necessary.

Check Stoplight Switch Circuit

Turn ignition switch to LOCK position. Disconnect ASCD control unit harness connector. Turn ignition switch to RUN position. Measure voltage between ground and terminal No. 11 (Red/Green wire) at ASCD control unit harness connector. See Figure . With brake pedal depressed, battery voltage should exist. With brake pedal released, zero volts should exist. If readings are as specified, ASCD brake/stoplight switch is okay. If readings are not as specified, go to next step.
Check for a faulty fuse No. 14 (10-amp), open or short in harness between ASCD control unit and stoplight switch, or a faulty stoplight switch. See SWITCHES under COMPONENT TESTS. Repair as necessary.