2003 Lincoln Navigator Power Running Boards

POLLOCK4842

MEMBER
2003 LINCOLN NAVIGATOR
V8
4WD
AUTOMATIC
98,000 MILES

We have a 2003 navigator and the power running boards have stopped working correctly. The drivers side works about 75% of the time and the riders side about
10-20% of the time. It will start out then retract and sometimes it won't come out at all. At times when someone steps on it to enter the thing will retract and almost catch your shoe/foot. Tried washing them off, spraying the arms underneath with WD40 with no luck. I read where in could be a relay or switch and do see wires going to a area under the car that's part of the running board arms. Not sure if this is one of the SW./Relays. My Mom is 96 and they really help in getting her in and out of the vehicle. Any help you can give me will be appreciated.
Thank You.

1 Reply

DAVE H

MECHANIC
13,383 POSTS

Hello .. thanks for the donation .. much appreciated

You will have to have the vehicle plugged into a diagnostic computer to locate the cause of the fault .. if there are no obvious signs of damage/wear

Principles of Operation
The retractable running boards are controlled by the power liftgate module and retractable running board motor assembly. The retractable running board motors receive a ground signal from the power liftgate module to deploy and an open signal to retract.
When the power liftgate module is in self-test mode, the retractable running board motor sends a 200 ms pulse to the power liftgate module to verify a deploy/retract command was sent by the power liftgate module. When the retractable running board reaches the fully deployed/retracted position, the retractable running board motor assembly will send a 200 ms pulse to the power liftgate module to indicate the operation is complete.
The power liftgate module receives information from the instrument cluster module (ICM) regarding retractable running board system ON or OFF and set for AUTOMATIC/IN or MANUAL/OUT status.
When in AUTOMATIC/IN mode, the retractable running boards will deploy when a door on the same side of the vehicle is opened. When both doors on the same side are closed, the retractable running boards will retract. The power liftgate module receives door ajar status from the body security module through the UART based protocol (UBP) communications network.
When in MANUAL/OUT mode, both retractable running boards will stay deployed until MANUAL/OUT mode is deselected or vehicle speed is greater than 5 mph.
When an obstacle is detected, the retractable running board will reverse direction. If a second obstacle is detected the retractable running board will reverse direction again. If a third obstacle is detected the retractable running board will stop in its current position until the following conditions are met:
Change in door ajar status.
Change in manual (OUT) deploy status.
Vehicle speed greater than 5 mph.
Inspection and Verification
Verify the customer concern.
Visually inspect for obvious signs of mechanical and electrical damage.
If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
If the concern remains after the inspection, connect the diagnostic tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
check that the program card is correctly installed.
check the connections to the vehicle.
check the ignition switch position.
If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool manual.
Carry out the DATA LINK DIAGNOSTICS test. If the diagnostic tool responds with:
CKT930 = ALL ECUS NO RESP/NOT EQUIP, refer to MODULE COMMUNICATIONS NETWORK .
NO RESP/NOT EQUIP for power liftgate module, refer to MULTIFUNCTION ELECTRONIC MODULE .
SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the power liftgate module.
If the DTCs retrieved are related to the concern, refer to Power Liftgate Module Diagnostic Trouble Code (DTC) Index to continue diagnostics.
If DTCs are retrieved that are not found in the following power liftgate module Diagnostic Trouble Code (DTC) Index, refer to the master power liftgate module Diagnostics Trouble Code (DTC) index in MULTIFUNCTION ELECTRONIC MODULE .
If no DTCs related to the concern are retrieved, GO to SYMPTOM CHART to continue diagnostics.

Hope this helps