HDJ81 RHD Driver Door Lock – What Controls the “Lift Handle to Lock” Function? (2 Viewers)

[Shaysoverlander]

Hey everyone,

I’ve got an imported RHD 1990 HDJ81 and I’m trying to better understand what specifically controls the behavior where the driver’s door will only lock if I flip the lock toggle and then close the door while lifting the exterior handle. From what I understand, this is a known quirk of JDM models, but I’m wondering if anyone has identified which part inside the latch or linkage system enforces this behavior.

I just rebuilt the driver’s door actuator assembly. I replaced the motor inside and everything seems to be working correctly. The actuator responds properly when tested off the truck, and it operates as expected when reinstalled. However, the electronic lock function won’t lock the driver’s door, whether it’s open or closed.

I have an aftermarket keyless entry receiver and key fob that I spliced into the door lock relay. It was working fine before the motor failed and I can use it to lock/unlock all doors but the drivers door. Now, the only way I can get the door to lock is by using the key or manually flipping the lock toggle and lifting the exterior handle while shutting the door this seems to align with the known JDM logic.

The actuator and latch look identical to pictures I’ve seen of US-spec FJ80 parts, but I’m guessing the difference is internal some kind of mechanical logic gate or cam that blocks the lock under certain conditions?

Has anyone:

• Pinpointed the exact internal piece (cam, spring, tab, etc.) responsible for this behavior?
• Swapped in a USDM latch to confirm if it removes this restriction?
• Successfully modified their JDM latch to behave like a USDM one?

Appreciate any insight or photos if you’ve dug into this before. I’m trying to decide if I need to source a US-spec actuator assembly/latch or just live with it.

 

[DivByZero]

It's not just Japan. All Toyota vehicles with manual door locks I've seen from the 90s were the same here in Australia, and honestly I didn't realise it wasn't worldwide until I saw this thread. It's supposed to make it less likely you accidentally lock your keys in the vehicle. It's a mechanical characteristic of the door handle mechanism, and happens even without central locking. If you don't lift the front door handles, the lock releases when the door is latched. Never studied the mechanism to see why, but you're looking for a mechanical linkage which forces the lock to release. The central locking triggering and unlocking the doors in your case is secondary - it's just triggering the unlock because it "saw" the lock get pushed into the unlock position.

 

[Irish Reiver]

Definitely not just a Toyota quirk. Every car we owned when i grew up in Ireland had the same locking principle. I always assumed the idea was not to accidentally lock the keys in the car.
Anyway, when i had an aftermarket remote locking unit fitted to my '94 I had the same issue. I vaguely remember the dude who fitted it having to splice a diode somewhere to override this issue. Sorry i can't help more that but it might get people thinking.