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Manual Switch Circuit

  1. Turn ignition off. Remove tilt and power telescopic ECU from its mounting, leaving wiring harness connector attached. Measure voltage by backprobing rear of terminals No. 17 (Red/White wire) with voltmeter positive lead and terminal No. 16 (Violet wire) with negative lead at 18-pin ECU harness connector T10. See Figure. Operate manual switch in each position and note voltage reading. See MANUAL SWITCH CIRCUIT VOLTAGE  table. If voltage is not as specified, go to next step. If voltage is as specified, go to next test listed in SYMPTOM DIAGNOSIS  table under TROUBLE SHOOTING.
    MANUAL SWITCH CIRCUIT VOLTAGE

    Switch Position Voltage
    Telescopic Extend 2.05-2.75
    Telescopic Retract .65-.95
    Tilt Down .30-.50
    Tilt Up 1.30-1.70
  2. Turn ignition off. Disconnect 18-pin tilt and power telescopic unit (combination switch) harness connector. Measure resistance between terminal No. 4 (Red/White wire) with voltmeter positive lead and by backprobing rear of terminal No. 6 (Violet wire) with negative lead at tilt and power telescopic unit (combination switch) harness connector. See Fig 1. Operate manual switch in each position and note resistance reading. See MANUAL SWITCH RESISTANCE  table. If resistance is as specified, go to next step. If resistance is not as specified, replace tilt and power telescopic unit (combination switch) and retest system operation.
    MANUAL SWITCH RESISTANCE

    Switch Position Ohms
    Telescopic Extend 160
    Telescopic Retract 790
    Tilt Down 1,990
    Tilt Up 360
  3. Check wiring harness and connectors between tilt and power telescopic ECU and tilt and power telescopic unit (combination switch). See WIRING DIAGRAMS . Repair or replace as necessary. If wiring harness and connectors are okay, check tilt and power telescopic ECU. See TILT & TELESCOPIC ECU PIN VOLTAGE TESTS  under COMPONENT TESTS. Replace tilt and power telescopic ECU as necessary and retest system operation.
Fig 1: Testing Manual Switch
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