Bus +/- Signals Open From Automatic Temperature Control Module
NOTE:
Automatic Temperature Control (ATC) module may also be referred to as ATC head.
- Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, select BODY, then BODY COMPUTER. If scan tool communicates with Body Control Module (BCM), go to next step. If scan tool does not communicate with BCM, perform BUS +/- SIGNALS OPEN FROM BODY CONTROL MODULE test.
- Turn ignition off. Disconnect Automatic Temperature Control (ATC) module connector. Turn ignition on. Using a 12-volt test light connected to ground, probe ATC module connector terminal No. 10, fused ignition switch output circuit (White wire). See Fig 1 . If test light illuminates, go to next step. If test light does not illuminate, repair open or short in White wire.
- Turn ignition off. Measure resistance between ground and ATC module connector terminal No. 1, ground circuit (Black/Light Green wire), and between ground and ATC module connector terminal No. 3, ground circuit (Black wire). If resistance is less than 5 ohms on both circuit, leave ATC module connector disconnected, and go to next step. If resistance is 5 ohms or more on either circuit, repair open in Black/Light Green wire and/or Black wire.
- Turn ignition off. Connect Scope Input Cable (CH7058) to channel one connector on scan tool. Connect Red and Black leads and Cable-To-Probe Adapter (CH7062) to scope input cable. Go to next step.
- Using scan tool, select DRB STANDALONE, LAB SCOPE, LIVE DATA, then 12-VOLT SQUARE WAVE. Press F2 for scope. Press F2 again and use down arrow to set voltage range to 20 volts. Press F2 again. Go to next step.
- Connect Black lead to chassis ground. Connect Red lead to ATC module connector terminal No. 2, PCI bus circuit (Violet/Yellow wire). Turn ignition on. Observe voltage display on scan tool lab scope. If voltage pulses from zero to about 7.5 volts, replace ATC module. If voltage does not pulse from zero to about 7.5 volts, leave ATC module connector disconnected, and go to next step.
- Turn ignition off. Disconnect BCM connector C1. Measure resistance of PCI bus circuit (Violet/Yellow wire) between ATC module connector terminal No. 2 and BCM connector C1 terminal No. 4. See Figure and Fig 1 . If resistance is less than 5 ohms, replace BCM. If resistance is 5 ohms or more, repair open in Violet/Yellow wire.
NOTE:
Steps 4
- 6
are written specifically for use with Chrysler's Diagnostic Readout Box (DRBIII(R)) scan tool.