Sensor Testing
With Tester J-22368 installed according to instructions, run engine at a fast idle, set Comfortron control lever to HI-FRONT, set Rocker switch to MANUAL, and set Manual Control Knob to 150 ohms on scale, then proceed as follows:
- Set the Tester Voltage switch to AMPLIFIER, and rotate Comfortron Temperature Dial until the Tester voltmeter reads 6.5 volts and Comfortron Temperature Dial should read 75°F. If it does not, see ADJUSTMENT for instructions to set the dial.
- 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.
- 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.