B1917-15

B1917-15-CABIN TEMPERATURE SENSOR - CIRCUIT SHORT TO BATTERY OR OPEN

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The HVAC A/C Heater Control uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Control to assure that they are in range. An active Diagnostic trouble Code (DTC) indicates that a sensor is out of range. A stored DTC indicates that the sensor was out of range but is currently within range.

The In-Car Temperature Sensor uses a temperature thermistor which changes in its resistive value with differences in air temperature of the interior cabin. Air is drawn from the passenger compartment by an aspirator (small fan driven by a 12-volt electric motor) which circulates air over the temperature thermistor. The A/C Heater Control uses the resistance value to calculate the temperature and make any adjustments to maintain the optimum passenger compartment comfort. The In-Car Temperature Sensor cannot be adjusted or repaired and is incorporated into the A/C Heater Control and is not serviceable.

- When Monitored:
With the ignition on.

- Set Condition:
When the In-Car Temperature Sensor signal to the A/C Heater Control is greater than 4.9 volts for a continuous period of two seconds or more. If the DTCs status changes from active to stored, the DTC will stay in memory for 100 ignition cycles.





Always perform the HVAC Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.

1. CHECK IF DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, read HVAC DTCs.

Is this DTC active?

Yes

- The In-Car Temperature Sensor in incorporated into the A/C Heater Control and is not serviceable. Replace and program the A/C Heater Control. A/C And Heater Control - Removal.

No

- Go To 2

2. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. With the scan tool, check the Environmental Data to help identify the conditions in which the DTC was set.
3. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
4. Wiggle the wiring and connectors while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Test complete.