Rear lift gate will not lock (every time)

[judoant]

Yesterday I realized my rear lift gate / hatch was not locking. I tried with the remote and the drivers side power lock switch. No dice. Standing at the rear of the truck I do not hear the power lock motor making any noise. Fast forward about an hour and 20-30 lock / unlock sequences it started to work again. Lock and unlock, both remote and door switch now work like new. I can also now hear the motor.

Today after about 10-20 lock/unlocks it quit again. I came home, took apart the lift gate, disconnected the backdoor ecu and all the harnesses I could find and put it all back together not finding anything obvious. Low an behold it works again, but for who knows how long.

Any ideas? Anyone else have this issue? I have no clue how to trouble shoot this when it goes bad except to maybe have a back door ecu and back door lock motor on standby and when it fails again start replacing parts. This is not the route I wanna go. Could another switch or relay somewhere other then the lift gate be going bad? I do know that my lift gate key lock has been frozen up and not worked for years.

I have a repair manual that shows how to test for continuity on these locks but I am not sure if my cheap harbor freight multi meter will do that or where to start.

 

[4Runner_101]

had a 4runner with this same issue and its pretty common, i needed a new latch lock. if grease dont fix it, most likely yours is gone too, just grab one from the scrap yard

 

[judoant]

Do you recall if power lock motor made any noise when you tried to lock/unlock? Cause when mine does not work the power lock motor does not even try to move.

 

[541joseph]

Lock actuator.

 

[judoant]

Lock actuator.

Replace the lock actuator? Do you think the rear window ecu is ok?

 

[541joseph]

Replace the lock actuator? Do you think the rear window ecu is ok?

It's possible it's bad but I'm thinking it's probably the actuator

 

[judoant]

I replaced both the actuator and the latch lock. Still no action on the actuator to lock or unlock. Guess I will replace the rear ecu?

 

[judoant]

I should have pulled out the multi meter before I started ordering parts. I do not have power at the door lock actuator when you press the door lock/unlock. I pulled the wiring schematic and I guess I am going to test each connector in the circuit till I find voltage. This is all new to me but Im figuring it out.

 

[judoant]

Well there seems to be an issue with the connector located in the roof at the drivers side rear. It is a BR1 10 pin harness. Toyota does not sell this harness so I guess I will have to cut one out of a junker.

How would you go about replacing this harness? can you pull the pins out and put them back in or cut about 6" of the replacement harness and just splice the wires back?

It very strange. i am not sure where the trouble is but if I fold the harness out of the head liner the lock works. When I place it back in the head liner it quits.

 

[.bg.]

Did you ever have any luck tracking down where the problem was on this?

I've got the same issue and just pulled out the solenoid to test- seems to work fine when hooked up to 12v directly, but there's no power getting to it.

 

[96RedRunner]

Check the wires where they pass from main body to hatch at the top. The wires flex every time you raise and lower the hatch. Mine had the copper strands broken, wire jacket good. Locked intermitently till it wouldnt anymore.
Sorry I don't remember the colors its been a while.

 

[.bg.]

Check the wires where they pass from main body to hatch at the top. The wires flex every time you raise and lower the hatch. Mine had the copper strands broken, wire jacket good. Locked intermitently till it wouldnt anymore.
Sorry I don't remember the colors its been a while.

Thanks, this was exactly it!

The wires are Black/Yellow and Blue/White on my '96 for anyone else's reference.

Thanks for the help!