mandyfig

Thanks for the link, hoping I will not need it....

namantm

I am having the same problem with my 2003 SC 430 with 155,000 miles. I can unlock the driver and passenger doors from the driver side and from the remote, but the door lock switch on the passenger side stopped locking or unlocking the door. So that rules out the actuator and the motor. I replaced the switch but that did not solve the problem. I checked the fuse and connection and they are fine. Is there a separate relay that controls the passenger-side door lock? Any help would be appreciated.

VVTiBob

yes, there is a passenger door ECU. Not too expensive on the 2nd hand mkt if yours has died.

namantm

Thank you so much for that information. Blessings!

Bgw70

what was the corrective action?

namantm

Replace the passenger door multiplex computer (ECU) as shown in the diagram. You can find a used one on E-bay for $25-30. New one costs about $140. There is no relay that controls the door lock. Just a fuse.

mandyfig

2 years later, I do not remember how I fixed this issue. Must not be a whole lot expense or time since I can not remember. Or maybe its me, nowadays I tend to forget stuff...

namantm

namantm

By replacing the Multiplex computer (ECU) in the passenger door as shown in the photos, I was able to fix the door lock. Simple repair procedure as follows:

0. Disconnect the battery and carefully pry on the door lock window panel with a plastic removal tool as shown, and disconnect the electrical connectors
1. Remove the three screws at the bottom of the door panel
2. Remove the two push pins at the front of the door panel
3. Remove the two screws at the back of the door panel
4. Remove the trim plate behind the door handle and remove the screw behind it
5. Remove the large screw below the arm rest
6. Remove the trim piece over the sub-woofer by carefully pulling it out
7. Roll the glass all the way down
8. Pull up on the door panel and it should come right out
9. Disconnect the electrical connector to the seat control panel from the back of the door panel
10. Pry out the two clips that hold the hold the wires on the ECU tabs
11. Disconnect the three wiring connectors from the ECU
12. Remove the two 10 mm screws that hold the ECU to the door
13. Reverse these steps after installing the replacement ECU, and reconnect the battery