Diagnostic Test

WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

TEST FOR INTERMITTENT CONDITION
NOTE:
Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.
1. Turn the ignition on.
  NOTE:
  Make sure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.
2. With the scan tool, read the module status.
  NOTE:
  Check the BCM for any active CAN hardware DTCs, perform DTC before proceeding.
  
  Does the scan tool indicate that the module is active on the bus?
  
  Yes
  - The no response condition is not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
  No
  - Go To 2
CHECK THE FUSED B(+) CIRCUIT FOR AN OPEN OR SHORT
1. Turn the ignition off.
2. Disconnect the A/C Heater Control harness connector.
3. Using a 12-volt test light connected to ground, check the Fused B(+) circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 3
  No
  - Repair the open or short in the Fused B(+) circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE GROUND CIRCUIT FOR AN OPEN
1. Using a 12-volt test light connected to 12-volts, check the Ground circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 4
  No
  - Repair the open in the Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE FUSED RUN RELAY OUTPUT CIRCUIT FOR AN OPEN OR SHORT
1. Turn the ignition on.
2. Using a 12-volt test light connected to ground, check the (F921) Fused Run Relay Output circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 5
  No
  - Repair the open or short in the Fused Run Relay Output circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE CAN INTERIOR BUS (125K) CIRCUITS FOR AN OPEN
1. Measure the resistance of the (D264) CAN Interior Bus (125K) (-) circuit between the BCM harness connector and the A/C Heater Control harness connector.
2. Measure the resistance of the (D265) CAN Interior Bus (125K) (+) circuit between the BCM harness connector and the A/C Heater Control harness connector.
  Are the resistances below 5.0 Ohms?
  
  Yes
  - Replace the A/C Heater Control Module in accordance with the Service Information. Refer to CONTROL, A/C AND HEATER, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Repair the open in the CAN Interior Bus (125K) circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .