On my 2004 LS430 base model, since the weather turned cold the front right door lock has been hesitant to lock and unlock. Sometimes it locks/unlocks with the first click on the 'key', but sometimes it takes three clicks. I can see the manual lock move a little more each time I press the unlock button on the 'key' or on the driver's door. The most it takes is three clicks.

Since this didn't start until the weather got cold, I think it could simply be due to the 20-year-old lubricant on the mechanism having lost its slipperiness.

What do y'all think?
- If it's a lubricant problem, what do I need to re-lube? (And, is there anything that can be lubed w/o removing the door panel?)
- If not a lubricant problem, then is it the 'actuator problem' that has been written about so well in this forum?

Remember: I've had this car through many winters, but this started with this fall's cold weather. The problem occurs only with the right front door lock. (If I didn't frequently have a passenger, I would not have noticed this.) Repeating clicks on the electric unlock button move the manual lock button a little each time, and then it's unlocked. Sometimes, however, there's no problem.

Many thanks.

 

The lube in the lock is one possibility, but the motors used in these door locks also need replacing as they wear out and get weak.
Plenty of articles on the forum about replacing the motors, but it is generally easier to just replace the whole mechanism if you can find a good used one.