Power lock problem: Locksmith, dealer, or some third option?

The electronic lock on the driver side door of my 91 Toyota Previa has ceased to work. First, the key just won’t go all the way in on the driver-side lock, so it can’t be unlocked from the outside on the driver side. For a few days after the onset of this problem, I was at least able unlock the driver-side door (and all other door locks) using the key on the passenger door, but eventually this stopped working too. (While I could open all the other power locks from the passenger side, the driver-side lock would stall (i.e., toggle half-way open and stop); the toggle could not even be manually advanced to the unlocked position from the inside, and thus I could not manually open the driver-side door at all, making it necessary to go through the passenger door for both entry and exit.) The latter problem has now proved intermittent: sometimes unlocking the driver-side door from the passenger-side lock is effective, but sometimes the driver door reverts to the toggle-stall problem described above. One thing is constant: I cannot get the key in the driver side door: it goes in to what seems like about 90-95% and appears to hit some sort of obstruction. Why that would mess up electronic operations from the passenger-side door—even intermittently—is a mystery to me. In all events, who do I take the thing to in order to get the problem resolved? Locksmith, Toyota dealer, or somewhere else?

WAG – I’d go to the dealer.

I would go to your local Toyota dealer. You probably need a new cylinder on your driver side and the wiring checked out on the rest of the car. As I wrote that last half sentence, it made me wonder if you burnt out some wires. Perhaps as the mechanism that unlocks your driver side door got jammed it over heated and caused electrical problems. If your good with cars (or with taking things apart and putting them back together in general), you could pop the door panel off and take a look your self.

I love taking things apart and I’m reasonalby good at getting them back together again. Once I get the panel off, what am I looking for?

I’m not really sure. Just be careful taking the panel off. Do it slowly and evenly. Anyways, I suppose if I were doing it, I would check for things like any burnt wires. Voltage going to the locks, anything that looks out of the ordinary. Hard to say without seeing it myself. If you do take it apart, tell us what you find. Like I said, it’s kinda tuff to diagnose without being there with a flashlight and a multimeter myself, but we’ll do the best we can. Have you ever done any electrical work on cars before (that is, do you understand the concept of a negative ground, and how to check to make sure all your grounds are good). If you don’t we can help with that to. Or if you really want to you could also pick up a Chilton or Haynes manual ( I don’t remember which, but I belive it’s Haynes that I like more).

If you take the door panel off, be careful not to tear or cut any of the insulating material inside, or you’ll be having wind noise and air leaks for the rest of the car’s life.

As “things to take apart and put back together” go, I’d wager a guess that electronic door locks might not be one of the simpler kind.

I am not familiar with the previa Door panels or really familiar with the toyota way of auto locking everything.

The door panel should come off easy enough just be patient ans careful and all will be well. Once off follow the linkcage rods in the door cavity. These you can check easy and they lead to everything else. Make sure they are not binding. The latch is where they all come together Somewhere near there should be a cylinoid that might have a short causing it to randomly crap out on you. A chiltons manual would most likely have some guildance about voltage and such.
Also, while you are in there take the lock out. If it is not part of the handle assembly it is a cake walk, remove clip and remove linkgage rod. Take the lock out, check to see if you can hold the housing and insert the key all the way. If not, something might veyr well have been broken off inside the lock or a wafer has gotten worn and bent. With the lock out you can drop it off at a locksmith shop and they should be able to repair it with ease.

If you cannot figure it out after poking around the dealer might be the best option to fix it.

My first thought is that you have two separate problems. While they might be related, the key not going fully into the cylinder and intermittent balkiness in the motion of the mechansism are two different and discrete aspects of the lock system.

As for the key/cylinder problem, a locksmith, dealer, or independent auto repair shop could handle this. First, though, I’d try a couple simple things. Try using a different key. It’s a bit of a long shot, but it’s not unheard of for an old key to be problematic where a less-used one works fine–and it’s very quick and easy to try (I hope you–and everybody–has at least one spare car key). Second, try cleaning/lubing inside the cylinder. Lock de-icer spray (pressurized if possible) just might help flush out some piece of debris. So might WD-40, which will also lubricate. Powdered graphite is the preferred lubricant for lock cylinders, since it won’t gum up or get stiff when cold. Try any or all of these to see if it helps.

On the failure to unlock, a dealer or independent shop could help you. I’m don’t know whether a locksmith could or not. If I understand correctly, it consistently responds to the switch, but sometimes only moves halfway and jams. The most common cause of this type symptom is stiffness in the mechanism (latch, linkage, etc.), usually caused by lack of lubrication or wear. If you’re really lucky, you might be able to get some WD-40 onto the balky parts without pulling the door panel. Roll the window down and try to get some sort of skinny light source so you can see any visible mechanism, and aim the nozzle at it. Work the lock/unlock lever manually, then see if it will work electrically.

Perhaps it wasn’t clear in my last suggestion above, spray the WD-40 through the slit in the top of the door body. With the window down, part of this slit should be unobstructed.

      • Regular WD-40 isn’t lubricant. It is primarily kerosene-based, it is intended to free sticky parts by dissolving out old lubricant. If your [whatever] already doesn’t have enough lubricant, WD-40 won’t help you any. It only “lubricates” when it’s wet, for the same reason gasoline is slippery. After the WD-40 evaporates, the problem is even worse than before. —Nowadays they might be making WD-40 with actual lube in it, but the regular stuff has no such thing.
  • Modern car locks are supposed to be lubricated with dry powder. Go to a gun shop and ask for Remington Dri-Lube or anything similar: powdered teflon in an evaporating carrier. Hose your locks with this every couple months for good karma. Powdered teflon is white and won’t stain clothes; if they offer something with moly-sulfide instead, be warned that moly-sulfide is another good dry-lube but it’s a jet-black powder that stains everything permanently.
  • Secondly, the OP didn’t give any location, so I dunno if this matters or not, but don’t use alcohol-lock de-icers unless you have no other choice. These wash the lube out of door locks and don’t do anything to replace it. Instead get a hot cup of water if possible and slowly pour it over the lock face. This usually warms the lock up enough to open it. Of course the lock will freeze up again when it gets cold, but before it does, squirt some dry-lube in it to drive out the water.