Hello,

So a few days ago my Driver side door would not unlock with the key, goes in but does not turn either direction. Had this issue before but with a little jiggling I have been able to unlock it in the past.
However, this time I was not able to and I was away from home so I called a locksmith to pop the lock. This set the car alarm off, and from what I can tell unless I can unlock with the key in the door the alarm will
continue to go off. Any way around this? When I bought the car there was no key fob. I tried to buy a blank one and reprogram the key fob to just lock/unlock (don't need it to start). I could not get the car to go into program
mode, suspecting this is because the alarm is going off?

Think the door lock cylinder is busted, could not find any parts online to replace.

 

Driver's door lock key cylinder cable is Honda Part number:72185-TA0-A01.

 

I posted about trying to get around my car alarm, I have gotten the door apart and have removed the back half of the key-lock cylinder and exposed the part that turns and turns inside the door actuator. I hooked my battery back, alarm still going, I close the door and make sure it latches, I then manual turn the **** which does lock and unlock the door now but the alarm never stops. I was going to replace the key-lock cylinder but seems that it wont fix the issue.

This started because I could not unlock my door with the key and my car didn't have a key fob when I bought it and a locksmith came to unlock my car and that alarm has been active ever since.

 

The cause may be due to a faulty driver's door lock actuator or a wiring issue. The Driver's Door **** Switch and Driver’s Door Key Cylinder Switch (electronic switches) are part of the driver's door lock actuator/latch assembly.

Service manual has continuity tests which can be performed of the respective switches.

 

Thank you for that information, I have found the service manual online and I see there is a module that connects the windows/lock/unlock buttons. I have been locking and unlocking the door as describe above but the window module was not connected, do you think that could be the reason for the alarm not disarming? Am going to try and connect it today and attempt it again. From what I can tell in the manual it sends a single through that window module.

 

The driver's door multiplex control unit (mcu) is part of the driver's door master switch assembly; so, that would have something to do with it. When you use switches from the driver's master switch, all lock and unlock commands from these switches are communicated across the multiplex communication line (i.e., a one wire B-Can communication line) to the multiplex integrated control unit (micu) located in the under-dash fuse/relay box.

As you probably already know; the security system can be deactivated by unlocking the driver’s door with the Driver’s Door Key Cylinder Switch or by pressing the UNLOCK button on the Keyless Transmitter. The communication has to go through the driver's door mcu.

Attached is the circuit diagram which shows the circuit connecting the Driver's Door **** Switch and Driver’s Door Key Cylinder Switch (electronic switches) which is part of the door lock actuator assembly to the driver's door MCU, which then connects to the under-dash MICU.

There seems to be an open (break) somewhere along the circuit.

So, the problem can be (but, not limited to):

• Driver's door master switch (mcu is part of this assembly)
• Wiring
• Driver's door lock actuator assembly (door know switch and driver's door key cylinder switches are part of this assembly)
• Under-dash MICU (I don't think this is likely though)

 

Wow, impressive post! I want to say thank you for such a detailed and informative post! I did not have the driver's door multiplex control unit connected the first time I was trying to reset the alarm. After reading your post I hooked everything back up and was able to use a flat head to turn the **** on the back of the key cylinder and this locked and unlocked the whole car, which reset the alarm system. I have the key cylinder on the way here. Should just be as simple as installing that and will be back in business. Thank you again for the information and your help. Part cost me 60 bucks instead of 550 quoted from the dealer for troubleshooting and install.