99 Accord door lock multiplex location?

1999 Accord. 4 cylinder with 134,000 miles. Sometimes door locks will not lock/unlock when locked/unlocked with the key or with the lock/unlock button.
FSM shows two multiplex control units: behind fuse panels on driver or passenger side. I cannot find which one controls the door locks. Could somebody tell me this before I start taking my car apart?
Oh yes, I bought the car with the aftermarket alarm that had the same feature: one push on the remote button unlocked all doors and the second push on the same button will lock all all doors. About a year ago I stopped using it. I appreciate your help.
Regards, Sam
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somick wrote:

they both do.
GW
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On Thursday, March 20, 2014 8:32:27 PM UTC-7, Geoff Welsh wrote:

e > lock/unlock button. > > FSM shows two multiplex control units: behind f use panels on driver > or passenger side. I cannot find which one controls the door locks. > Could somebody tell me this before I start taking my car apart? > > Oh yes, I bought the car with the aftermarket alarm that had the same > feature: one push on the remote button unlocked all doors and the > second push on the same button will lock all all doors. About a year > ago I stopped using it. I appreciate your help. > > Regards, Sam > > they both do. GW
Thanks for reply. I plan to work on it this weekend. I will report back if I ever find anyth ing.
Sam
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somick wrote:

they both do. GW

Actually there's three.
It'd be far easier to diagnose with a fully capable scan tool. The drivers switches (key, button, & lever) ALL communicate with the DOOR MCU, which communicates with the drivers side MCU and it, in turn, communicates with the passenger MCU, and that one controls all the lock motors. Most likely problem is always the part that moves the most, and that'd be the comm wire through the drivers door A-pillar, or the DOOR MCU (in the door.)
GW
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On Friday, March 21, 2014 6:35:11 PM UTC-7, Geoff Welsh wrote:

ometimes door locks > will not lock/unlock when locked/unlocked >> with the key or with the > lock/unlock button. > > FSM shows two >> multiplex contr ol units: behind fuse panels on driver > or >> passenger side. I cannot fin d which one controls the door locks. > >> Could somebody tell me this befor e I start taking my car apart? > > >> Oh yes, I bought the car with the aft ermarket alarm that had the >> same > feature: one push on the remote butto n unlocked all doors >> and the > second push on the same button will lock all all doors. >> About a year > ago I stopped using it. I appreciate your help. > > >> Regards, Sam > > they both do. GW > > Thanks for reply. I plan to work on it this weekend. I will report > back if I ever find anything.

nicate with the DOOR MCU, which communicates with the drivers side MCU and it, in turn, communicates with the passenger MCU, and that one controls all the lock motors. Most likely problem is always the part that moves the mos t, and that'd be the comm wire through the drivers door A-pillar, or the DO OR MCU (in the door.) GW
Thanks, Geoff!
I figured it out. Before going for MCU, since I do not have a scanner, I d ecided to check the easy stuff - door lock actuators. As of now I have the rear passenger side actuator out of the car. To my surprise it does not w ork. The motor, when out of the actuator, spins easily in both directions. With the unlock button pressed the actuator makes a buzzing noise but doe s not move. It does move when I press the "lock" button. So most likely t his is my problem.
I am still trying to understand why it moves only in one direction. Mechan ically everything looks OK: no warn parts, plenty of lubricant.
Sam
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On Tuesday, March 25, 2014 10:44:09 AM UTC-8, somick wrote:

Sometimes door locks > will not lock/unlock when locked/unlocked >> with t he key or with the > lock/unlock button. > > FSM shows two >> multiplex con trol units: behind fuse panels on driver > or >> passenger side. I cannot f ind which one controls the door locks. > >> Could somebody tell me this bef ore I start taking my car apart? > > >> Oh yes, I bought the car with the a ftermarket alarm that had the >> same > feature: one push on the remote but ton unlocked all doors >> and the > second push on the same button will loc k all all doors. >> About a year > ago I stopped using it. I appreciate you r help. > > >> Regards, Sam > > they both do. GW > > Thanks for reply. I pl an to work on it this weekend. I will report > back if I ever find anything . > > Sam > Actually there's three. It'd be far easier to diagnose with a f ully capable scan tool. The drivers switches (key, button, & lever) ALL com municate with the DOOR MCU, which communicates with the drivers side MCU an d it, in turn, communicates with the passenger MCU, and that one controls a ll the lock motors. Most likely problem is always the part that moves the m ost, and that'd be the comm wire through the drivers door A-pillar, or the DOOR MCU (in the door.) GW

he rear passenger side actuator out of the car. To my surprise it does not work. The motor, when out of the actuator, spins easily in both direction s. With the unlock button pressed the actuator makes a buzzing noise but d oes not move. It does move when I press the "lock" button. So most likely this is my problem.

I decided to take the actuator's electrical motor apart and found out that the brushes were worn down to the brass brush holders. Under load the moto r apparently did not get good contact with the commutator and stopped.
There was no sense buying new brushes and trying to fit them when the new a ctuator on Ebay cost 11 dollars with free shipping.
So the multiplex control unit was not my problem. Door locks work now.
Thanks to everybody who helped me.
Regards, Sam
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somick wrote:

so ONE malfunctioning actuator caused ALL the doors locks to not work sometimes.
Great follow-up, thanks.
GW
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