Intermittent Door Lock Issue
05-28-19, 06:36 PM
#1
Driver School Candidate
Thread Starter
Intermittent Door Lock Issue
Hi All:
I have a 2000 LS400 and just started having issues with the the door locks. When I press the door lock/unlock switch several times, I noticed that both my rear locks will actuate intermittently. The rear driver side actuates less frequent than the rear passenger, but occasionally they do work. So I decided to pull off the rear driver door panel and took out the lock actuator. I cracked it open, everything looked fine. I pulsed the motor (without a load) with 12V and worked fine. Contacts on the position sensor looked fine. The relay controller is receiving power, and when I switched the power, I noticed that the motor side connector was getting voltage (couldn't tell it was exactly 12V because it was so fast on the multimeter). I took apart the relay controller, everything looked fine, no burnt contacts or anything.
When I switch the locks very slowly at like a once every 10 or 15 seconds, all locks seem to work fine, but when I switch much faster, that's when I see the issue for both rears. It works for the few toggles but after that it basically slows down sort of like the local capacitors don't have enough energy to pulse the motor normally. I can hear the relays clicks.
Do you think I can rule out the lock actuator and relay controller (I guess it's called the multiplex computer)? Should I look elsewhere?
Any suggestions would be great. Thanks!
-David
I have a 2000 LS400 and just started having issues with the the door locks. When I press the door lock/unlock switch several times, I noticed that both my rear locks will actuate intermittently. The rear driver side actuates less frequent than the rear passenger, but occasionally they do work. So I decided to pull off the rear driver door panel and took out the lock actuator. I cracked it open, everything looked fine. I pulsed the motor (without a load) with 12V and worked fine. Contacts on the position sensor looked fine. The relay controller is receiving power, and when I switched the power, I noticed that the motor side connector was getting voltage (couldn't tell it was exactly 12V because it was so fast on the multimeter). I took apart the relay controller, everything looked fine, no burnt contacts or anything.
When I switch the locks very slowly at like a once every 10 or 15 seconds, all locks seem to work fine, but when I switch much faster, that's when I see the issue for both rears. It works for the few toggles but after that it basically slows down sort of like the local capacitors don't have enough energy to pulse the motor normally. I can hear the relays clicks.
Do you think I can rule out the lock actuator and relay controller (I guess it's called the multiplex computer)? Should I look elsewhere?
Any suggestions would be great. Thanks!
-David
Last edited by dcwang3; 05-28-19 at 06:43 PM.
05-28-19, 09:20 PM
#2
Moderator
Hi All:
I have a 2000 LS400 and just started having issues with the the door locks. When I press the door lock/unlock switch several times, I noticed that both my rear locks will actuate intermittently. The rear driver side actuates less frequent than the rear passenger, but occasionally they do work. So I decided to pull off the rear driver door panel and took out the lock actuator. I cracked it open, everything looked fine. I pulsed the motor (without a load) with 12V and worked fine. Contacts on the position sensor looked fine. The relay controller is receiving power, and when I switched the power, I noticed that the motor side connector was getting voltage (couldn't tell it was exactly 12V because it was so fast on the multimeter). I took apart the relay controller, everything looked fine, no burnt contacts or anything. To change the motor is another way to fix.
When I switch the locks very slowly at like a once every 10 or 15 seconds, all locks seem to work fine, but when I switch much faster, that's when I see the issue for both rears. It works for the few toggles but after that it basically slows down sort of like the local capacitors don't have enough energy to pulse the motor normally. I can hear the relays clicks.
Do you think I can rule out the lock actuator and relay controller (I guess it's called the multiplex computer)? Should I look elsewhere?
Any suggestions would be great. Thanks!
-David
I have a 2000 LS400 and just started having issues with the the door locks. When I press the door lock/unlock switch several times, I noticed that both my rear locks will actuate intermittently. The rear driver side actuates less frequent than the rear passenger, but occasionally they do work. So I decided to pull off the rear driver door panel and took out the lock actuator. I cracked it open, everything looked fine. I pulsed the motor (without a load) with 12V and worked fine. Contacts on the position sensor looked fine. The relay controller is receiving power, and when I switched the power, I noticed that the motor side connector was getting voltage (couldn't tell it was exactly 12V because it was so fast on the multimeter). I took apart the relay controller, everything looked fine, no burnt contacts or anything. To change the motor is another way to fix.
When I switch the locks very slowly at like a once every 10 or 15 seconds, all locks seem to work fine, but when I switch much faster, that's when I see the issue for both rears. It works for the few toggles but after that it basically slows down sort of like the local capacitors don't have enough energy to pulse the motor normally. I can hear the relays clicks.
Do you think I can rule out the lock actuator and relay controller (I guess it's called the multiplex computer)? Should I look elsewhere?
Any suggestions would be great. Thanks!
-David
The quickest way to fix is to replace the actuator. Dealerships only do so and charge you $$$. I usually only replace the Posistor purchasing it at Akihabara Tokyo. Problem is that the part is not available easily.
Last edited by Yamae; 05-28-19 at 09:36 PM.
05-29-19, 03:16 AM
#3
Driver School Candidate
Thread Starter
Hmmm that’s interesting. I really appreciate the explanation. I didn’t realize the actuators had a ptc in it. I did measure the resistance across the dc motor terminals and it was showing approximately 6-7ohms.
From a Japanese forum that I saw that had information about removing the door panel and cleaning the dc motor, they mentioned the resistance was around 3-4ohms. So you mentioning the initial resistance of the ptc ages, which sounds consistent.
do you know what the part number is of the ptc?
or it’s actually probably better just ordering a whole actuator from amazon, just need to make sure it’s the correct size and shaft. How would the original leads get transferred to the new actuator? I am assuming it’s just solder points?
From a Japanese forum that I saw that had information about removing the door panel and cleaning the dc motor, they mentioned the resistance was around 3-4ohms. So you mentioning the initial resistance of the ptc ages, which sounds consistent.
do you know what the part number is of the ptc?
or it’s actually probably better just ordering a whole actuator from amazon, just need to make sure it’s the correct size and shaft. How would the original leads get transferred to the new actuator? I am assuming it’s just solder points?
Last edited by dcwang3; 05-29-19 at 03:38 AM.
05-29-19, 05:31 AM
#4
Moderator
Hmmm that’s interesting. I really appreciate the explanation. I didn’t realize the actuators had a ptc in it. I did measure the resistance across the dc motor terminals and it was showing approximately 6-7ohms.
From a Japanese forum that I saw that had information about removing the door panel and cleaning the dc motor, they mentioned the resistance was around 3-4ohms. So you mentioning the initial resistance of the ptc ages, which sounds consistent.
do you know what the part number is of the ptc?
or it’s actually probably better just ordering a whole actuator from amazon, just need to make sure it’s the correct size and shaft. How would the original leads get transferred to the new actuator? I am assuming it’s just solder points?
From a Japanese forum that I saw that had information about removing the door panel and cleaning the dc motor, they mentioned the resistance was around 3-4ohms. So you mentioning the initial resistance of the ptc ages, which sounds consistent.
do you know what the part number is of the ptc?
or it’s actually probably better just ordering a whole actuator from amazon, just need to make sure it’s the correct size and shaft. How would the original leads get transferred to the new actuator? I am assuming it’s just solder points?
The one I used last time was this below marked C965 ..... manufactured by TDK.
https://www.tdk-electronics.tdk.com/..._C945_C995.pdf
Since this has to be set outside of the motor and it can't detect the motor's temperature well. So I use it at my own risk.
The best and the quickest way is to replace the whole actuator unit paying about $200 each.
I haven't try this but there may be a way to buy a newer motor and replace only the PTC thermistor if the sizes and the specifications are the same.
05-29-19, 06:54 PM
#5
Driver School Candidate
Thread Starter
This is great information. I took apart the pinion gear thinking that it was just a rounded shaft motor that I would need, but found out that it had splines. So after all this, I decided to order whole new lock actuators.
The car has Aisins and I found the same ones that it suppose to fit the 2000 ls400 for a reasonable price. We will see how they work.
thanks for the help!
The car has Aisins and I found the same ones that it suppose to fit the 2000 ls400 for a reasonable price. We will see how they work.
thanks for the help!
05-30-19, 04:34 PM
#6
Change the little motor and you should be fine, I did this about 10 years ago, I order the small motor on eBay and crack open the black actuator and replace little motor, working perfect ever since I also did this fix to my land cruise it’s a super common issues for Toyota. You might notice it worst in summer time
03-20-21, 03:34 PM
#7
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There are lots of references in this thread about taking the motor apart (fc-280pc-22125) flat shaft and OEM PAN14EE12BC motor then putting the top plastic piece on the old original OEM motor resulting in an OEM solution . But I find that getting the tabs on the motor to pry up enough is almost impossible because the thickness of the metal does not easily bend and no room for the tools. Does anyone know of a way or a tool that can bend the tabs to get the motor apart ?
Still trying !!!
Thanks so much if you can help !
Still trying !!!
Thanks so much if you can help !
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