Test 11A: Inoperative Control Head Switch
WARNING: This page is about a different car, the 1999 Dodge Intrepid and 1999 Chrysler Concorde. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Before proceeding with this test, perform TEST 1A: IDENTIFYING A/C-HEATER SYSTEM PROBLEMS
.
- If problem is with A/C switch, go to step 3 . If problem is with rear defogger switch, go to next step.
- Using scan tool, select BODY COMPUTER, SENSORS and observe MODE SWITCH MUX voltage. Press and hold rear defogger switch. If voltage is about 0.2 volt when switch is pressed, switch is operating properly at this time. If voltage is not about 0.2 volt when switch is pressed, replace A/C-heater control head. Perform VERIFICATION TEST .
- Using scan tool, select BODY COMPUTER, SENSORS and observe MODE SWITCH MUX voltage. Press and hold A/C switch. If voltage is about 0.4 volt when switch is pressed, switch is operating properly at this time. If voltage is not about 0.4 volt when switch is pressed, replace A/C-heater control head. Perform VERIFICATION TEST .
NOTE:
If A/C switch is operating properly, and A/C switch LED does not
operate, check for an open in FAN OFF SWITCH SIGNAL circuit. If BCM sees a
blower motor off (fan off) signal it will not illuminate A/C switch LED. Check
for open Violet/Light Green wire between A/C-heater control head and BCM.
Repair as necessary.