Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) TEST FOR INTERMITTENT CONDITION
Turn the ignition on.

Clear all FCM DTC's

Turn the Left Turn Signal on.

With the scan tool, read DTC's.

Does the scan tool read: B1644-REAR LEFT TURN CONTROL CIRCUIT HIGH?

Yes
1. Go To step 2).
No
1. The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
2. Perform BODY VERIFICATION TEST - VER 1 .
2) LEFT REAR TURN SIGNAL BULB
Turn the ignition off.

Inspect the Left Rear Turn Signal Bulb Assembly.

Is the inoperative bulb OK?

Yes
1. Go To step 3).
No
1. Replace the Inoperative bulb in accordance with the service information.
2. Perform BODY VERIFICATION TEST - VER 1 .
3) L63 LEFT TURN SIGNAL CONTROL CIRCUIT

Fig 1: Checking L63 Left Turn Signal Control Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the IPM C2 connector.

Disconnect the Left Rear Tail Lamp assembly.

Measure the resistance of the (L63) Left Rear Turn Signal Control circuit.

Is the resistance above 5.0 ohms?

Yes
1. Repair the (L63) Turn Signal Control circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Go To step 4).
4) FRONT CONTROL MODULE

Fig 2: Checking Front Control Module
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Front Control Module from the PDC 49-way connector.

Measure the voltage between (L63) Left Rear Turn Signal Control circuit and ground in the PDC.

Is there any voltage present?

Yes
1. Replace the Power Distribution Center.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Replace the Front Control Module.
2. Perform BODY VERIFICATION TEST - VER 1 .