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Virtual Wrench
Virtual Wrench, Honda Mechanic
Category: Honda
Satisfied Customers: 14612
Experience:  35 years Master Mechanic
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Honda Odyssey EX-L I replaced the passenger multiplex unit

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I replaced the passenger multiplex unit on my 03 EXL navi Odyssey to fix a non-operative master control window switch that would not roll down passenger window. After doing this, the window issue went away; but, the closer assembly ceased working on the driver side slider door. (slider motor works; but, not the closer motor) So, I replaced the closer assy to no avail. Possible that the multiplex i installed was not the correct one? Any other diagnostics?

Thank you.


Trying to diagnose this online is rather difficult and i can't say i can give you an exact cause for this, but i can send you a nice wiring diagram and show you where i think may be the circuit involved if that is acceptable with you just let me know. Otherwise i can opt out and you can try to wait it out and see if someone is going to be able to tell you an answer right off the top.

Let me know please.
Customer: replied 5 years ago.
Thank you for response.
At this point, I'll reinstall the old multiplex unit first. If that fixes it (and causes the window issue again) then I know it's in the multiplex somehow.
I know where the circuit is. lower left kick panel.

Check the green wire and connections that goes from the multiplex to the door switch that tells the multiplex when the door is closed, so the closing actuator will work. See below.


Let me know how it turns out.

Customer: replied 5 years ago.

Thank you.
Customer: replied 5 years ago.
I will check the green wire and connectors first. If nothing, then old unit is going back in.
Fair enough.

Let me know if you can't find anything and we can go from there but that sure ties in to the area you were working and the involvement of that switch to complete the circuit so the actuator works.

Virtual Wrench and 3 other Honda Specialists are ready to help you
Customer: replied 5 years ago.
I double checked the multiplex and the large plug on the back was not securely fastened. Once i locked the plug in, it worked.

Thank you for your time.

I'll accept your answer.
Hot Dog!

Good work, and thanks for asking! Please take a moment for some feedback.
Virtual Wrench and 3 other Honda Specialists are ready to help you
Customer: replied 5 years ago.
Just thought this should be followed up on. It seems that the real issue when replacing a multiplex in the '03 Odyssey is that when securing the unit, it seems to displace wires resulting in loss of continuity. Once I buttoned everything up, and thought the job was finished, my wife got in and noticed the electric seat back adjuster wasn't functioning. I immediately backed off pressure on the two retaining bolts for the fuse box/multiplex, which in turn resolved the problem. So, the lesson learned is that there are so many electrical connections to the multiplex, that it's too easy to disrupt circuitry when refastening the unit, which will result in a whole host of strange issues such as TCS and ABS lights coming on, door closer failure and power seat failure.

Now, isn't technology marvelous?

"Now, isn't technology marvelous".....welcome to my world.... day in and day out we run into this with electrical issues and can be a real hair puller!!

Thanks again!