All,

The title pretty much sums it up. Engine running or not, with the key in the "on" position, the car will automatically lock the doors anytime the driver's door is closed. The only caveat is that it it doesn't just lock immediately. When the door is closed, it will go "unlock" "unlock" "lock". Happens every time. Help! This is on a 2003 Accord 4cyl.

Thanks!

 

The issue can be due to either:

• an open (break) in the Wht/Blk wire between the driver's door unlock switch and multiplex control unit
• a bad driver's door actuator.

There was a July 2005 Honda Service News article:

Power Doors Lock By
Themselves or Cycle Twice
NOTE: This article applies to ’03–05 Accords,
’05 Odysseys, and ’06 Ridgelines.

An open (ungrounded) driver’s door lock ****
unlock switch can cause the multiplex-controlled
power door locks to lock by themselves or to
cycle twice to unlock and then lock.

What’s going on is the multiplex control unit
"thinks" the driver’s door is locked. To try and
restore the unlock signal, the system unlocks the
door twice. The system then goes back to its
default position by locking the doors.

To fix this problem, here’s what you need to do:
1. Connect the HDS to the 16P data link
connector (DLC). Turn the ignition switch to
ON (II). Turn on the HDS.

2. At the screen prompts, enter the VIN and the
odometer reading.

3. From the Select Mode screen, select Honda
Systems. From the System Selection
Menu, select Body Electrical.

4. Select Door Locks, and then select Data List.

5. Scroll down to the driver’s door lock (unlock)
data, and read the screen. The list says ON
when the door lock **** is unlocked; OFF
when it’s locked. If the driver’s door lock input
is incorrect, go to step 6.

6. Check for an open circuit in the WHT/BLK
wire between the door multiplex control unit
and the driver’s power door lock switch. If the
wires and connections are OK, go to step 7.

7. Check the lock **** switch ground. If it’s OK,
then replace the driver’s door lock actuator.

 

Thank you for the great info. Where is the multiplex unit located?

 

The driver's door multiplex control unit is integrated as part of the driver's door main door lock/window switch.

 

The Wht/Blk harness wire can be tested for continuity after you unplug the harness connector from the actuator side and the driver's door MCU. To test for continuity, set the multimeter to either the "ohms" or the setting it will beep when you hold the two leads together.

• If your meter beeps, it means you have continuity.
• If it is on ohms scale, you will have continuity when it reads close to 0 ohms.
• If it doesn't beep , shows OL (open line) or a 1 (infinity ohms); it means you don't have continuity.

 

Thank you! Are either of these parts (switch or actuator) common failures?