LF Door Lock Actuator Troubleshooting

[Rev Run D]

89 Sedan

The LF door doesn't unlock using the key. The PO installed an alarm system so that the keyless entry can open the door.

Also, the central locking works through the trunk and the RF door lock.

I pulled the door panel off, and removed the key cylinder to troubleshoot. It doesn't bind, opens and closes properly, so it's not the culprit. After searching the forums, it looks like the actuator might be the culprit.

What do I need to do to troubleshoot it? Is it a simple R/R job, or is there adjustments that need to be made?

[Rev Run D]

Update: The door locks/unlocks if I use my finger to move the actuator lever through the hole the key lock goes through. So it seems like somehow the physical connection between the actuator and the key cylinder isn't engaging. I've compared it to pictures of e30 cylinders i've seen online, and it doesn't look like anything is broken.

[itsonlygeorge]

There is a small microswitch that is part of the lock cylinder mechanism and it may be broken or worn out. You should do some research on that and find out what needs replacing. Could also be a short somewhere.