A/c-Heater System - Automatic: Overview Chrysler LHS I

DESCRIPTION

The Automatic Temperature Control (ATC) system provides for manual or automatic control of passenger compartment air. When automatic mode is selected, system controls blower speed, temperature, and airflow.

Automatic temperature control is canceled when full heat or full cool is selected.

The system has self-diagnostic capabilities and will store trouble codes for later retrieval. Trouble codes can be retrieved using ATC panel or DRB scan tester.

Note. For basic A/C-heater system components not covered in this article (except LHS), see A/C-HEATER SYSTEM - MANUAL article in the AIR CONDITIONING & HEAT section.

TEST 17A - ATC CLUTCH OPERATION

Note. Perform TEST 2A before proceeding with this test.

1. Turn ignition on and engine off. Using DRB, select CLIMATE CONTROL MENU, then select SYSTEM TESTS and then select A/C ON TO BCM. Using DRB, observe A/C switch status while pressing A/C switch. If DRB displays A/C SW: CL when switch is pushed and A/C SW: OP when switch released, go to next step. If display is not as specified, replace ATC head. Perform «VERIFICATION TEST»(ref-11044-S27712653502001011200000) . NOTE: Look for ON or OFF messages during the following steps. Ignore NR messages.
2. Start engine and turn A/C switch on. If DRB displays BCM: ON, go to next step. If DRB does not display BCM: ON, replace BCM. Perform «VERIFICATION TEST»(ref-11044-S27712653502001011200000) .
3. If DRB displays SBEC: ON, go to next step. If DRB does not display SBEC: ON, replace PCM. Perform «VERIFICATION TEST»(ref-11044-S27712653502001011200000) .
4. Using DRB, read PCM codes. If DRB does not display any trouble codes, go to next step. If any of following climate control-related PCM trouble codes are displayed, see appropriate TESTS W/CODES article in the ENGINE PERFORMANCE section: ECT SENSOR VOLTAGE TOO LOW ECT SENSOR VOLTAGE TOO HIGH A/C PRESSURE SENSOR VOLTS TOO HIGH A/C PRESSURE VOLTS TOO LOW LOW SPEED FAN CONTROL RELAY CIRCUIT HIGH SPEED FAN CONTROL RELAY CIRCUIT A/C CLUTCH RELAY CIRCUIT ENGINE IS COLD TOO LONG
5. Turn ignition on and engine off. Locate A/C clutch connector on top of compressor. Disconnect A/C clutch connector and ensure connector is clean and not damaged. Using DRB voltmeter, probe A/C clutch connector Dark Blue/Black wire to A/C clutch relay output. Using DRB, actuate A/C clutch relay. If voltage is less than 10 volts, go to next step. If voltage is greater than 10 volts, replace A/C clutch. Perform «VERIFICATION TEST»(ref-11044-S27712653502001011200000) .
6. Locate A/C clutch relay at No. 3 position in Power Distribution Center (PDC). Remove A/C clutch relay. Using DRB voltmeter, probe PDC A/C clutch relay terminal "B" (Red/Light Green wire). If voltage is greater than 10 volts, go to next step. If voltage is less than 10 volts, repair Red/Light Green wire between PDC A/C clutch relay and PDC fuse "D". Perform «VERIFICATION TEST»(ref-11044-S27712653502001011200000) .
7. Using external ohmmeter, measure resistance of Dark Blue/Black wire between PDC A/C clutch relay position and A/C clutch connector. If resistance is less than 5 ohms, replace A/C clutch relay. Perform «VERIFICATION TEST»(ref-11044-S27712653502001011200000) . If resistance is greater than 5 ohms, repair open Dark Blue/Black wire.