Diagnostic Test

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT FOR AN OBJECT HOLDING THE SWITCH IN THE 'ON' POSITION
1. Inspect the A/C Heater Control for an object or debris holding the Rear Window Defogger control switch in the ON position.
2. With the scan tool, read the On/Off status of the control switch.
  Is the control switch being held in or stuck On?
  
  Yes
  - The A/C Heater Control cannot be repaired or adjusted and must be replaced if inoperative or damaged but it might be cleanable if external debris is inhibiting the proper operation of the control switch or knob. If you are unable to clean the control so it can function properly, replace and program the A/C Heater Control in accordance with the Service Information. Refer to CONTROL, A/C AND HEATER, REMOVAL .
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 2
CHECK FOR AN ACTIVE DTC
1. With the scan tool, read DTCs and record on the repair order.
2. Record the Environmental Data.
3. With the scan tool, erase DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. With the scan tool, read HVAC Module DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the A/C Heater Control in accordance with the Service Information. Refer to CONTROL, A/C AND HEATER, REMOVAL .
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .