Possible free fix for door lock actuators (worked on my 98 anyway)
Ok, so when I was a Ford mechanic, we used to fix door lock actuators for customers (not under warranty) by disassembling the actuator motor itself and wrapping the thermal resistor in foil.
Out of curiosity, I was replacing another of the Taiwanese junk ebay actuators that had again stripped out and I thought about taking a look at the factory actuator motor to see if it had a similar thermal resistor that used to fail in the Fords. Well, it does - at least my wife's 98 Avalon does. The motor is contained within the latch assy itself and once removed, you can pull the plastic end cap off the motor and wrap that silver rectangular disk (thermal resistor) in foil and reassemble and as with the Fords, the lock now has significant power and works like a brand new one.
It should be said though that my understanding is that the thermal resistor is a protection device to save the motor from burnout in the case of abuse.
Anyway, check it out.. cant beat the price of a tiny piece of aluminum foil for this fix.
The "thermal" resistor sounds what is also called a "fusible link." It is a fuse in series that will fail before the motor overheats. Fusible links are used as sort of a last resort protection. A seized motor can cause very high currents which might even lead to a fire. You might find that you can actually buy a new "thermal resistor" instead of removing this safety device.
Last edited by ImDisaster; 05-02-2010 at 02:45 PM.
The "thermal" resistor sounds what is also called a "fusible link." It is a fuse in series that will fail before the motor overheats. Fusible links are used as sort of a last resort protection. A seized motor can cause very high currents which might even lead to a fire. You might find that you can actually buy a new "thermal resistor" instead of removing this safety device.
The only fusible links i have dealt with open completely under their rated high current and do not again close. The door lock circuit is still fused, so I feel pretty safe bypassing it, but others may choose to do differently. I think it is there to reduce current before motor failure if a child were to continually hit the switch as so many of them do. But, YMMV.
cbd1, is this what causes the door not to lock? I have a 95 XL, and my driver side rear door does not lock, and recently I found that my passenger side rear door is not opening at all, from inside or out?
cbd1, is this what causes the door not to lock? I have a 95 XL, and my driver side rear door does not lock, and recently I found that my passenger side rear door is not opening at all, from inside or out?
Well, this particular issue is with the lock actuator, so it's a pretty good bet that it'll fix the one that won't unlock. It's free, so it's worth a shot anyway.
As far as the door that wont open from either side.. well... you have to remove the whole latch to do this fix anyway, so you may as well do it on that one too and fix the latch/linkage while you are in there..
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How on earth were you able to remove the actuator? I removed the door panel and was able to get all the arms off except for the inside-lock-to-latch arm. I followed the chilton manual directions pretty strict and still was not able to get the door latch off. I'm assuming the actuator is located on that door latch. I too have a 98 avalon and the front passenger door lock wont unlock/lock with the keyless entry and I can feel a slight vibration in the door when attempting to unlock/lock with the keyfob so I'm hoping all it needs it this aluminum foil trick. If only I could get the actuator out! Any help would be appreciated.
yes, the actuator motor is in the lower portion of the latch assy. There is a small Phillips head screw that holds that plastic weather shield over the latch assy which will have to come off to move the shield to get that last rod off if I remember correctly. Then you can remove the torx in the door jam that hold the latch assy to the jam. The first one is pretty painful, but after that they get easier. Beer helps.
Hmmm, ok I'll try and take another look at it this weekend. Lets say that the aluminum foil trick doesn't work, how would I go about replacing the actuator? Would any ole universal door lock actuator do? I can't seem to find a model number or replacement part for this anywhere. What do you recommend cbd1?
I would try the foil trick. I believe it will work for you. I also think that the factory actuator comes as part of the entire latch assy and is a couple hundred bucks. However, the Chinese universal actuators do work for awhile, at least until they break or strip out. Mine were lasting about 3-4 months each until I gave up and dissected the latch. The thing is to take your time and be patient if you try this fix. Walk away when you begin to get frustrated and come back later. It's a tough latch to get out of the door the first time and taking the latch apart on the bench needs to be done carefully as well. I would take pictures if you think you may run into trouble during reassembly. Also, I remove the window glass first and then the rear window track inside the door. It only takes a minute to do this and it really frees it up in there to work.
This is the foil trick done on a Ford truck which is the same internal motor, so start on page 2 about halfway through the pics once you get the actual motor out of the latch housing. There are a couple of metal tabs bent in to hold the plastic end of the motor housing on. You'll need to bend these flush with the case to remove the plate and access the thermal resistor. Then, when you go to reinstall the plate, there are a couple of small holes in the plate that will allow access to the brushes so that you can separate them with a needle and get them over the bushing and back onto the commutator. Having a bench vice will be almost entirely necessary. Best of luck! Once you do one, the others go fast.
it just routes current around the resistor rather than through it. You could also use solder across the contacts on each side of the foil and gain the same effect, but this is easier. I think that there is some discussion of the component itself on the Ford trucks link that I posted above.
Hey cbd1, so I've been working on my door this afternoon and after some work was able to get the door latch mechanism off. I disconnected all four of the connecting rods to the door latch, where the two that lead to the outside door handle and lock are attached to the latch mechanism itself. Its here where I really need your assistance, cbd1. I've found several more sites on this topic and even found a step by step picture tutorial on replacing the little motor but it was done on a lexus and the latch assembly looks quite a bit different than my avalon. I could use the advise from someone who has done this on an avalon before.
I have the whole assembly out and on my work bench but on the assembly are a number of plates and arms that operate with the connecting rods going to the outside door handle and lock and inside door handle and lock. These plates seem to be restricting my ability to open up the compartment containing the motor. I'm hesitant to use much force and pry the plates off since if I brake one or bend one in the wrong direction, the door may not operate correctly thereafter. I removed four screws on the assembly that seem to hold the hood of the compartment on and when I begin to try and pry this hood off, one of the arms I mentioned earlier is restricting it and something else seems to be resisting too. I dont want to force anything and break something. What do you recommend I do to gain access to the motor itself? Can you describe to me what you did once you had the latch assembly separated from the door? I would appreciate it a lot.
sure, you are on easy street now.. It looks harder than it is....
I'm doing this from memory, but:
There are, I believe 3 flush-mount Philips head screws on the striker side of the latch assy. Remove these. Then, the bottom plastic piece will separate. Pull it apart at the very bottom seam with it flipped striker side (screw removal side) down. There is one gold linkage connection from the motor and it's assy to the rest of the latch and it is through a small red/brown colored plastic bushing. The piece of linkage that protrudes through the red bushing will slide out from behind it once you separate the black plastic motor and gear housing as described. You just have to lift the lower edge up pretty high to get the linkage at about a 45deg angle and then it will allow you to slip that flat bladed linkage out through the back side of the red bushing/grommet. Once this is in your hand and separated from the latch, the rest is fairly obvious.
I wish I had taken pics.. But I think that the advice you need is that you don't need to disassemble all of those linkage pieces as the lower portion is all that has to come off the latch assy.
Last edited by cbd1; 06-13-2010 at 10:27 AM.
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Thanks cbd1, I was able to finally get the gear housing separated from the latch assembly. I ended up purchasing a replacement motor, a Mabuchi FC-280PC-22125 which is pretty much a direct replacement to the original. A few modifications needed to be done to the gear housing and terminal pin but it fit perfectly.
I reassembled it with the latch assembly, tested it out, and realized that now its performing backwards. I reconnected the lock and window switch panel, pressed down to lock, and the latch assembly moves into the unlocked position, vise-versa, press unlock and it moves to the locked position. I thought it could have been my wiring that was the problem but it should have been the same as the original motor. I tried switching a few gear directions thinking that might possibly do something, but nothing changed. I fiddled around with the latch assembly and gear housing for a good two hours before calling it quits and throwing it back into the door only keeping the wiring disconnected to the door handles and locks still functioned. I am completely stumped at this point and could use an extra opinion or two as to what might be the problem. I studied the inside of that gear housing in and out and absolutely stumped. I am much better with mechanical systems, while electrical and wiring are a little out of my realm so maybe it was the wiring that was the problem, maybe my positive and negative leads need to be switched. Does anybody have some advice?
BTW, I have the schematic of the motor from the manufacturer and labeled that the right lead was the positive and the left lead was negative. Assuming the design of the leads was the same as the factory motor, I left it was the green wire was positive and the yellow was negative. Maybe I'll check and see what my chilton manual has labeled as the positive and negative leads.
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