Diagnostic Procedure

WARNING: This page is about a different car, the 2004 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.

NO RESPONSE FROM HVAC - DIAGNOSTIC PROCEDURE

TEST	ACTION
1	Turn the ignition on. With the DRB, enter Body then Body Computer. Was the DRB able to I/D or communicate with the CTM? Yes --> Go To 2 No --> Refer to the symptom list for problems related to no communication with the CTM. Perform BODY VERIFICATION TEST - VER 1 .
2	Turn the ignition off. Remove and inspect fuse #25 in the junction block. Is the fuse open? Yes --> Go To 3 No --> Go To 6
3	Turn the ignition off. Replace Fuse #25 in the junction block. Turn the ignition on. Remove and inspect fuse #25 in the junction block. Is the fuse open? Yes --> Go To 4 No --> Check the Fused Ignition Switch Output circuit for an intermittent short to ground, refer to the SYSTEM WIRING DIAGRAMS . Perform BODY VERIFICATION TEST - VER 1 .
4	Turn the ignition off. Replace fuse #25 in the junction block. Disconnect the A/C Heater Control C1 harness connector. Turn the ignition on. Remove and inspect fuse #25 in the junction block. Is the fuse open? Yes --> Go To 5 No --> Replace the A/C Heater Control in accordance with the service information. Perform BODY VERIFICATION TEST - VER 1 .
5	Turn the ignition off. Disconnect the A/C Heater Control C1 harness connector. Disconnect the Junction Block C11 harness connector. Measure the resistance between ground and the Fused Ignition Switch Output circuit. Is the resistance below 5.0 ohms? Yes --> Repair the Fused Ignition Switch Output circuit for a short to ground. Perform BODY VERIFICATION TEST - VER 1 . No --> Replace the Junction Block in accordance with the service information. Perform BODY VERIFICATION TEST - VER 1 .
6	Turn the ignition off. Disconnect the A/C Heater Control C1 harness connector. Using a 12-volt test light connected to 12-volts, probe the ground circuit. Is the test light illuminated? Yes --> Go To 7 No --> Repair the Ground circuit for an open. Perform BODY VERIFICATION TEST - VER 1 .
7	NOTE: Ensure fuse #25 is installed in the junction block. Turn the ignition off.Disconnect the A/C Heater Control C1 harness connector.Turn the ignition on.Using a 12-volt test light connected to ground, probe the Fused Ignition Switch Output circuit.Is the test light illuminated? Yes --> Go To 8 No --> Repair the Fused Ignition Switch Output circuit for an open. Perform BODY VERIFICATION TEST - VER 1 .
8	NOTE: Ensure there is PCI Bus communication with other modules on the vehicle before proceeding. If not, refer to the symptom list from the menu and repair as necessary. Disconnect the A/C Heater Control C1 harness connector.Use Scope input cable CH7058, Cable to Probe adapter CH7062, and the red and black test probes.Connect the scope input cable to the channel one connector on the DRB. Attach the red and black leads and the cable to probe adapter to the scope input cable.With the DRBIII(R) select Pep Module Tools.Select lab scope.Select Live Data.Select 12 volt square wave.Press F2 for Scope.Press F2 and use the down arrow to set voltage range to 20 volts. Press F2 again when complete.Connect the Black lead to the chassis ground. Connect the Red lead to the PCI Bus circuit in the A/C Heater Control connector.Turn the ignition on.Observe the voltage display on the DRB Lab Scope.Does the voltage pulse from 0 to approximately 7.5 volts? Yes --> Go To 9 No --> Repair the PCI Bus circuit for an open. Perform BODY VERIFICATION TEST - VER 1 .
9	If there are no possible causes remaining, view repair. Repair Replace the A/C Heater Control in accordance with the service information. Perform BODY VERIFICATION TEST - VER 1 .