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Manual Switch Circuit

  1. Connect Lexus Hand-Held Tester (scan tool) to Data Link Connector 3 (DLC3). Turn ignition and tester on. Select DATALIST mode on tester. Check voltage while operating manual switch. If scan tool is not available, remove tilt and telescopic ECU with harness connectors connected. Turn ignition on. Measure voltage between 22-pin ECU connector (T9) terminal No. 18 (Red/Yellow wire) and 12-pin ECU connector (T8) terminal No. 2 (White/Black wire). See Figure.
  2. Operate manual switch in each position and note voltage reading. See MANUAL SWITCH VOLTAGE table. If all voltages are as specified, go to TROUBLE SHOOTING and identify next circuit to be checked. If all voltages are not as specified, go to next step. If voltage in only certain directions is not as specified, replace switch.
    MANUAL SWITCH VOLTAGE

    Switch Position Volts
    Telescopic Out (Extend) 2.05-2.75
    Tilt Up 1.30-1.70
    Telescopic In (Retract) .65-.95
    Tilt Down .30-.50
  3. Remove tilt and telescopic ECU with harness connector connected, if not done in step 1). Turn ignition on. Measure voltage between 22-pin ECU connector (T9) terminal No. 21 (Blue wire) and ground. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go step 5).
  4. Disconnect 10-pin manual switch wiring harness connector. Measure resistance between manual switch connector terminals No. 4 and 9. See Fig 1. Operate manual switch in each position and note resistance. See MANUAL SWITCH RESISTANCE table. If resistances are as specified, go to next step. If resistances are not as specified, replace tilt and telescopic manual switch.
  5. Check wiring harness between tilt and telescopic ECU and manual switch. See WIRING DIAGRAMS. Repair as necessary. If wiring harness is okay, go to TROUBLE SHOOTING and identify next circuit to be checked.
MANUAL SWITCH RESISTANCE

Switch Position Ohms
Telescopic Out (Extend) 160
Tilt Up 360
Telescopic In (Retract) 790
Tilt Down 1990
Fig 1: Identifying Manual Switch Connector Terminals
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