Door locks switch not working properly

JEASERVE

MEMBER
2008 HONDA PILOT
6 CYL
2WD
165,000 MILES

When I have the key in tune in the on position, the door lock switch works.
If I manually unlock the door and try to open the other doors with the switch, it won't work unless I use the key in the ignition in the on position.
The same happens with the courtesy lights. Unlock the driver side door and no lights, unless I have the key in the on position, then the lights go on. May likely be related.
Rafael

5 Replies

KASEKENNY

MECHANIC
18,907 POSTS

I suspect they are related. What I think is happening is the door lock switch in the door is either failing or the door multiplex control unit has failed.

What is supposed to happen when you use the key is the door control unit should wake up the body control module and that allows the switches to operate and the lights to come on. However, it seems like when the door is unlocked manually then the computer is not even seeing that the door is open and so it doesn't respond until you turn the key on.

So we need to start with checking for voltage at the multiplex unit in the door.

https://www.2carpros.com/articles/door-panel-removal

https://youtu.be/Hlna_kUt7As

Let us know what you find with this and then we will have a better idea on what to replace or direction to go next.

Thanks

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Saturday, April 17th, 2021 AT 5:24 PM

JEASERVE

MEMBER
3 POSTS

There appears to be three items to check. How do I know which one to check? Is there a video that shows where the locations are?
I have these similar issues as mentioned by someone else:

Interior lights do not turn on when doors are opened, or when buttons are depressed or when switch to the left of the steering wheel is flipped to the on position.
Power locks stopped working (though, there is a faint clicking sound at the passenger side fuse box when lock or unlock is pressed from either driver or passenger doors).
Driver window controls can only control driver window, but not any of the passenger windows. Passenger windows can be controlled from their respective doors.

System Unit, Multiplex Control(Driver Side) - Honda (38800-S9V-A21)
System Unit, Multiplex Control(Passenger Side) - Honda (38850-S9V-A21)

Receiver Unit, Keyless Entry - Honda (38385-S9V-A01)
Thank you very much for your help. Rafael

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