Since it makes no noise when you trigger the electric lock, it might(?) be a bad wiring connection. But I can understand having the actuator on hand saves you from maybe having to take the door apart twice.

Let us know what you find when you take it apart...

 

Short version: Mechanical part of old actuator was frozen (stuck). Electrical part of old actuator probably burned out. Replacing actuator fixed problem. Works perfectly now!

First picture shows old actuator. The part with pink clip is supposed to rotate. It did not, even if I tried to make it move. That's why manual lock button would not push down.

It took me a while to figure out the actuator was stuck, not something stuck within latch assembly. I was surprised, but glad, since I was dreading having to replace expensive latch assembly.

No idea why old actuator was frozen stuck, or if solenoid is still OK. Later, I may cut old actuator open and look inside, out of curiosity.

Second picture shows new actuator installed. Clip is purple in new actuator. Sorry that orientation flipped when image was uploaded.

For anyone working on the door lock mechanism, here are a few things I learned, IMO:

1) Difficult to test electrical inputs, because actuator electric connector does NOT allow attaching standard test leads. You would need two people, and even then awkward.

2) When taking apart, write down EXACTLY what you do at each step. Probably always a good idea, but especially for taking apart things behind the door.

3) Do NOT totally remove metal window channel. Instead, slide it down about two inches, and then fold rubber casing to the left and tuck into door (along with metal channel).

4) When reinstalling metal window channel, keep trying to slide upwards while wiggling it. Metal channel has to fit within another metal channel. Be patient and keep trying.

5) If metal window channel will not slide, take metal channel out from within rubber casing, lubricate things, and then slide metal channel into rubber casing.

6) Make sure to keep any greasy lubrication away from rubber casing where it touches window, when window slides.

7) When ready to snap door panel back in place, take a break, eat something, rest a bit. When you come back, make SURE everything is connected.

8) If you do not connect things correctly, and close door, you can end up not being able to open door (it happened). So double-check carefully before closing door.

9) Rod that goes to outside door handle is DIFFICULT to remove. Getting clip off is easy. But awkward to get rod out of door handle hole.

10) Do not need to disconnect (not easy) arm rest controls connector. Instead, can rotate still connected door panel 90 degrees and place on top of crate.

11) IMO, Not an "easy" job. The components are inside the door panel, awkward to access. Watching youtube videos helped some, but not that much.

12) I was dumb, did not write down what I did each step when taking things apart. Would have been a LOT easier to reassemble, avoided mistakes, if I had written down exact disassembly steps I took.

I hope maybe this helps someone else. Thanks to everyone who commented on my post.



Old actuator

New actuator in place

 

I opened up old (bad) actuator. See picture below.

Part with pink clip is supposed to rotate when the actuator runs. It does not rotate. It is stuck.

Black part is a sensor, to tell when the actuator has run and I guess turn it off. The sensor never functions because part with the pink clip never rotates.

Brown part is the actuator motor. It turns gears that are supposed to rotate part with the pink clip. Brown color is abnormal. You can see brown color migrated to inside of the plastic shell. Maybe something inside motor leaked out? Maybe motor got wet / rusted? Perhaps I will never know.

Again, new actuator is installed, after some trials and tribulations, and door locks work perfectly now.


2005 Honda Accord Hybrid passenger front actuator

 

Moisture got in there & the motor rusted.

That should be grease all around the worm gear?

The black component is a limit-switch to tell when the arm has moved.

 

Thanks. I wonder how the moisture got in there. It was not a recent event. Must have been slowly rusting over many years. Yet, everything continued to function. Until it finally froze up.

The rust color seems to have migrated (moved) some. That suggests to me there was more than a little moisture.

Yes, there was grease around the worm gear. The worm gear would not move.

Some of the white shiny specks you might see were bits of the plastic from when I cut open the actuator.