Electrical Circuit Test

If system operating properly and with Tester J-22368 connected as previously described, proceed as follows:

1. With engine running at fast-idle move Comfortron lever to MED., set rocker switch on Tester at MANUAL, set Tester manual control knob to 150 ohms on scale, and set Tester voltage switch to AMPLIFIER.
2. Rotate Comfortron temperature dial until Tester voltmeter reads 6.5 volts. Temperature dial should read "3". Adjust dial if necessary.
3. Run car at least 10 minutes with windows and doors closed, then switch Rocker switch to AUTOMATIC. Voltage reading should remain 6.5, with a change in voltage indicating a bad sensor.
4. If a bad sensor is indicated, check each sensor while it is disconnected from the system, using an ohmmeter. Approximate resistance of each sensor at 75°F. should be as follows:

   In-Car Sensor	50-75 ohms
   Ambient Sensor	55 ohms or less
   Feedback Potentiometer	70 ohms (approx.) with "O" vacuum in servo. 15 ohms (approx.) with 10 or more inches of vacuum on servo.
   Master Delay Thermistor	70 ohms
   High Blower Delay Thermistor	70 ohms

   NOTE: See SYSTEM CHECKS chart for details of Feedback Potentiometer check.