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Temperature Dial Calibration

NOTE: Allow sufficient time to allow full engine warm-up and the ATC system to come on.
  1. Connect ATC Tester J 23678 into the ATC wiring harness and the programmer, place Selector Lever at VENT. (See "TESTS").
  2. Place Manual-Automatic switch on tester in the MANUAL position and the Temperature Dial Calibrator switch on the tester in the CAL. position. Note the voltmeter reading on tester.
  3. Depress the COMPARE button on the tester and rotate the temperature dial on the control panel until the voltmeter reading is the same as noted in step 2).
  4. At this time the control panel temperature dial should read "75". If it does not, use Tool J 21530 to hold gear on left side of dial (insert toothed end of tool in slot beside gear), slip dial until correct reading obtained. If dial cannot be calibrated in this manner, it is defective and must be replaced.
    Fig 1: Temperature Dial Adjustment
    G09311436Courtesy of GENERAL MOTORS COMPANY
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