Door Lock Ghost...with a twist

[MyFirstRunner]

Hey all, hoping someone can help with some advice. '99 3.4L SR5 4WD 208K miles, . So, recently my door locks started going off the wall, locking/unlocking in rapid succession. Checking out some of the threads, I first replaced the battery in my key fob and that didn't stop the issue.

Here are a couple trends (though it is intermittent):

- Several times the locks began going haywire when the turn signal is activated...to the point where the locks were locking/unlocking in rhythm with the blinker (blink, blink, blink...lock, unlock, lock, etc.)
- Today I noticed that by turning on the rear defrost (nothing happened), but when I turned it off the doors would unlock. I was able to replicate that several times on the way to the grocery store, but it didn't do it on my way home.
- I have noticed that the locks would unlock/lock by using the power windows, though this was pretty random and not every time.

Okay, so that said, I assume it's either a wiring issue or an issue with the mother board. I was doing the LED swap on my gauges today and with the panels off I thought I could maybe see the if any of the wiring bundles looked frayed or anything but didn't see anything out of the ordinary...all looked clean, no metal burning smells.

I'm not really sure what to do here. Any ideas? Anyone had any similar issues? I think in the mean time I'm going to unplug all of my door lock actuators as this issue has already burned out one of the motors and I had to swap it.

Thanks in advanced!

 

[Mellemel]

Ahh someone else with this !! I will watch with interest. My 97' locks or unlocks suddenly when driving !! WTF ?? No where near as bad as yours seem to be. Sorry I cannot offer any help.

 

[MyFirstRunner]

Ahh someone else with this !! I will watch with interest. My 97' locks or unlocks suddenly when driving !! WTF ?? No where near as bad as yours seem to be. Sorry I cannot offer any help.

Thanks. Seems like it's either a wiring issue or something in the computer. Hopefully someone can offer some advice!!

 

[IBallEngineer]

Well I'm not going to speculate beyond the most obvious. The common denominator in all the circuits involved here are not that many. The Body ECU is involved in all of the stated items. They all are ultimately connected to ground and power. You could spend a lot of time isolating the faults by testing different circuits on the body ECU. Or you could try to get a known good one, and try swapping it.

Personally I don't like to guess, but that is all I have for you with this many variables. The instructions for testing the Body ECU are beyond the scope of going back and forth in a thread. If I had time to do a full write up with pictures and video, you might be able to follow that. But I don't have that kind of time, and the failure would be difficult to simulate anyway. I know I'm not being real helpful here, but I can tell you if it were me I'd be looking to swap the Body ECU. Preferably with a good used one for free.

:couch2:

 

[MyFirstRunner]

Well I'm not going to speculate beyond the most obvious. The common denominator in all the circuits involved here are not that many. The Body ECU is involved in all of the stated items. They all are ultimately connected to ground and power. You could spend a lot of time isolating the faults by testing different circuits on the body ECU. Or you could try to get a known good one, and try swapping it.

Personally I don't like to guess, but that is all I have for you with this many variables. The instructions for testing the Body ECU are beyond the scope of going back and forth in a thread. If I had time to do a full write up with pictures and video, you might be able to follow that. But I don't have that kind of time, and the failure would be difficult to simulate anyway. I know I'm not being real helpful here, but I can tell you if it were me I'd be looking to swap the Body ECU. Preferably with a good used one for free.

:couch2:

Thanks! That makes sense with the symptoms. I'll check out the junk yards next weekend!

 

[thegipper]

My 97 about 50% of the time has the door unlock go off after I start it. No clue why it happens, I just live with it...

Sent from my SM-N910V using Tapatalk

 

[spruce]

I'd be checking all the grounds.
Both posters are in rust prone areas.

I made my antenna stop going up and down randomly (on a clean Texas T4R) by changing the starter, alternator and battery but you may not want to go that far right off.

 

[catrains]

with a vehicle this old and the many electrical circuits involved this is most times a ground issue. the gound points get corroded and this is usually what happens [wierd operation of electrical devices]

 

[MyFirstRunner]

with a vehicle this old and the many electrical circuits involved this is most times a ground issue. the gound points get corroded and this is usually what happens [wierd operation of electrical devices]

Thanks for the reply! Which ground points are most vulnerable. Looking at the wiring diagram, there appear to be a ton of ground points. Suggestions?

 

[catrains]

Thanks for the reply! Which ground points are most vulnerable. Looking at the wiring diagram, there appear to be a ton of ground points. Suggestions?

ok your not going to find this on a diagram. open hood look for the ground points body/engine/frame. remove battery ground before you clean up these corroded ground points.

having a OEM manual this should show where the ground points are mounted . best to just check all the grounds you can find out side the vehicle where things get rusted.

what I do is clean up any corroded ground then after securing the ground wires paint a coating of undercoating over it to prevent future issues.

if the body is rusted up bad in the ground fastener move to another location with no rust for a good connection.also check battery ground points .

 

[MyFirstRunner]

ok your not going to find this on a diagram. open hood look for the ground points body/engine/frame. remove battery ground before you clean up these corroded ground points.

having a OEM manual this should show where the ground points are mounted . best to just check all the grounds you can find out side the vehicle where things get rusted.

what I do is clean up any corroded ground then after securing the ground wires paint a coating of undercoating over it to prevent future issues.

if the body is rusted up bad in the ground fastener move to another location with no rust for a good connection.also check battery ground points .

Thanks, I'll let you know how it goes. I've seen diagrams for other Toyota's but not for the 3rd Gen runner...bummer. Based on other diagrams I'm assuming there are 5 or so grounds I should be checking for in the engine bay...

 

[MyFirstRunner]

Hi, just wanted to close the loop on this. So big thanks to member Chim who was parting out his old 3rd Gen and sold me his Body ECU board. I swapped it with mine and all is resolved. It did take 3-4 days for the all of the bugs to smooth out but now I no longer have any door lock issues! Well, except for the fact that I think I burnt out the front passenger door lock actuator motor before I got the new ECU in. Added bonus, my power sunroof closes faster now...sweet!

Regarding the door actuators, I think it's mentioned in other threads, but if your door lock stops working or doesn't seem to have the power to open all the way, you don't need to replace the entire actuator, just the motor inside. What the posts don't tell you (or I missed it) is that the actuator won't snap back together. For mine I had to wrap them in duct tape.

I used these off of Amazon. https://www.amazon.com/gp/product/B00CM10NE8/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Thanks again for everyone's feedback!

 

[Juppers]

How old is your battery? Tested your alternator? Low voltage can cause all sorts of electrical gremlins to pop up.

 

[badattitude]

Glad yours is fixed, I'll leave my two cents for the next guy who finds this, it may help them.

My guess is the rear lock cylinder in the rear hatch has separated from the license plate bezel. The easy fix is to access and unplug and remove the locking cylinder. You need to remove the interior panel for access. I had the same problem and this fixed it. I used a plastic plug to fill the lock cylinder hole. The hatch still locks and unlocks with the fob and interior lock switch.

The lock cylinder is attached to plastic license plate bezel. Over time the plastic tabs that hold the lock cylinder to the plastic bezel break. This confused the lock position sensor and the truck can't tell if the hatch is locked or not causing the ghost lock. Simple fix is to unplug remove the lock cylinder only, then plug hole in bezel. You'll lose the ability to roll down rear window with the key but again the fob will still roll down rear window and the interior switch with roll down rear window.

 

[Hillside Inc.]

Same Issue - Ghost Lock

I too have a 1999 SR5 auto. 256k miles, factory VIP alarm.
It has been very cold here (it is 8 degrees F at the time i am writing this).
On Saturday, the runner started locking itself while driving; all doors would lock. Sometimes once, sometimes not at all.
On Sunday, the runner started locking itself several times a trip. When you hit the unlock button, all the locks pop up and immediately go back down.
On Monday, all the above issues are still happening, along with a new one. Now, if you open the door while the locks have engaged, all the locks cycle up down up down and don't stop unless the vehicle is shut off.
Tuesday (today) all the above happens, and now the locks cycle with the turn signal indicators and the hazard lights.

I thought there must be an issue with the lock cylinders possibly being frozen, until the issue with the lights and signals.
I am arranging to get a body ecu from another 99 SR5 auto, but I will go out with some 99% Iso alcohol and spray into the locks and turn them manually with the key.

Any ideas, thoughts, or comments?
I will update as my issues progress.

 

[Poor runner]

Hope this thread isn't too dead.

I am having some very similar symptoms as OP did in my 99 SR5. My door locks all go on and off at random, sometimes once, sometimes as many as 10 times. It happens even with the key out and after the truck has been parked for days.

Sounds like OP fixed these gremlins by replacing the "body ECU". I have never heard of a body ECU. Could you be more specific about which one it is and where it is in the car?

 

[Sparky 97Runner]

Could you be more specific about which one it is and where it is in the car?

The door locks on my 97 are controlled by an integration relay located to the left and below the steering wheel below the fuses. Toyota must have switched to this body ECU in 99 but I'm guessing it would be in the same location. Hopefully someone with a 99 wiring diagram manual can confirm. When I read the OPs first thread I would have guessed it was a grounding issue but it does sound like he resolved the issue by replacing the "Body ECU board".

 

[Sparky 97Runner]

Check out this thread. Post #5 has a picture of the board.
Body ECU test bad, or does it?

 

[Poor runner]

Thanks everyone, found the alleged culprit using a guide in this thread: Body ECU test bad, or does it?
Looks like he had a different control board that my truck.

The case continues... Gonna see if you can get a whole new control board or if I can just replace the faulty relay.

 

[ninethings]

had essentially the exact same thing happening to mine ('02 3.4 4wd 225k miles) when I lived back east. Happened on a drive from DC to NJ during a really bad rain storm. Locks wouldn't stop freaking out the entire drive back. Happened again intermittently with heavy rain, but I moved across the country to the desert and it hasn't been an issue since. Maybe just move to the desert? lol