I have a 2004 4 door V6 Accord.

I suspect this problem is electrical related, not mechanical.

Starting about a year ago, my power door locks would be funky - they always open just fine, but do not lock. I press the button on the driver side, then passenger side, and the wouldn't lock like 75% of the time. But the problem was very intermittent. Sometimes, they would work. Then I replaced my battery (nothing specific with the locks, I just needed a new one) and all of a sudden they worked perfectly again... for a few months. They've been dead again for a few days now, and it seems like they are 100% dead now. I haven't gotten them to close a single time since.

A few details:

-The locks (all 4 of them) always open just fine, weather I press the driver side, passenger side, or key unlock buttons
-The locks do not close at all now, regardless of if I press the driver side, passenger side, or key lock button
-If I manually close all the locks, and then I press the key lock button, I will get the alarm arming beep. However, if a lock is open I don't get that beep.
-Sometimes the airbag icon goes on in my dash, but it's intermittent. It's been like that forever. No clue if it has anything to do with the lock problem.

Because all 4 locks open just fine, but none of the 4 close, I doubt it's a mechanical problem with a lock. Since the behavior is also the same with the key, driver, and passenger side door switches, I also doubt it's a mechanical issue with the key. The fact that when it was happening the first time (intermittently) and then went away when I got a new battery, then came back after a few months leads me to believe that this is some sort of odd electrical issue.

This is certainly annoying, but not annoying to the point where I want to spend who knows how much money with a shop to get it fixed. However, if you may know what the culprit is or have experienced this, your advice would be appreciated!

 

May be an issue with either:

• driver's door multiplex control unit (MCU), built into the driver's door master switch
• or the under-dash MICU (Multiplex Integrated Control Unit), which is part of the driver's under-dash fuse/relay box.

The MICU controls the lock and unlock functions.

The multiplex control system probably got reset due to it not having power for a while during battery replacement. Which may be why the lock functioned properly for a few months.

You can try a battery cable reset (to reset the multiplex control system) by disconnecting the negative and positive cables and connecting them together with a jumper wire for 15 minutes. -- Do not touch the battery terminals.

 

So is it really critical that I leave it disconnected for 15 min? I killed power to my battery and reconnected to see if it would work, but it's still broken. If it's super critical that I wait 15 min, let me know and I'll try it again waiting for that long.

Otherwise what would you recommend the next course of troubleshooting be?

 

Ok so I tried the battery reset, this time left it unplugged for 30 min and jumped the cables. Still no joy...

So what would you recommend my next step be? Should I try changing the driver MCU first, change the under dash MICU first, or some further troubleshooting next?

I appreciate the help, thank you!

 

It is more likely it is a problem with the under-dash micu.

See this thread, which was solved by replacing that.

https://www.hondaaccordforum.com/for...-2005-a-52092/