Diagnostic Test

WARNING: This page is about a different car, the 2009 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

INTERMITTENT CONDITION
1. Turn the ignition on.
2. Using the scan tool, clear all FCM DTCs.
3. Turn the Headlamps on.
4. With the scan tool read the DTC information.
  Does the scan tool read: B1638-RIGHT HI BEAM CONTROL CIRCUIT HIGH?
  
  Yes
  - Go to step 2
  No
  - The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
RIGHT HIGH BEAM BULB
1. Turn the ignition off.
2. Inspect the Right High Beam Bulb Assembly.
  Is the inoperative bulb OK?
  
  Yes
  - Go to step 3
  No
  - Replace the Inoperative bulb in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
(L34) HIGH BEAM CONTROL CIRCUIT

Fig 1: Checking High Beam Control Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the FCM C2 harness connector.
3. Measure the resistance of the (L34) High Beam Control circuit.
  Is the resistance above 5.0 Ohms?
  
  Yes
  - Repair the (L34) High Beam Control circuit for a short to battery condition.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Replace the Front Control Module (FCM) in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .