2017 SR driver door locking - BCM?

Hi there! Just picked up a 2017 SR 2.7 ex-commerical vehicle to turn into a semi-camping-rig / daily.

I have scoured the site and internet for this issue, and come to the conclusion it's my BCM. I really don't want to buy one but here's my issue:

I noticed the driver door not unlocking the passenger door - and thought - no worries replace the actuator. Nothing. Bench tested and the motor works.

- At the plug for the actuator I get a test light on either of the 2 larger pins when I hit lock/unlock.
- The bench tested actuator that moves with power attached will not however work when plugged in. Is the test light giving less than 12v?
- Multimeter reads about 10V at the plug when I hit lock/unlock.
- DL fuse is good on box under steering wheel.

I have looked to see if there's any weird wiring going on. Assuming I need to buy a replacement BCM?


All the while hitting lock/unlock the passenger side works perfectly.


I cannot figure it out! Any help would be appreciated.

 

I don’t know if Tacomas use the standard reversing set up, but if you have power, how about ground? Are you trying to unlock vai keyless (which in sr trim is most likely aftermarket)?

 

Good point on the ground. I assume I do because my test light is clipped onto a bolt on the driver door when I test the actuator/latch pins. Anyone know if the motor uses ground from the door bolts that hold it in place?

My truck doesn't have keyless, so the buttons on the driver door work to lock/unlock the passenger side, and for the driver side I am just using key in the barrel. It only works for the driver door since the actuator won't work and send signal to the passenger side.

I don't really understand how the plug won't make the motor work. I was told the other 4 pins are position sensors for the actuator motor and can only think either one of the wires is bad, or the BCM is bad.

Not sure how to test. Continuity test all the wires from the actuator plug back to the cab somewhere?

 

Bump. When I close the driver door and jump in I also hear a double click in the passenger door.
Can't figure it out. Checked the BCM and all the pins and wires look good.
Baffled. Auto electrician ?

 

@caribe makaira

Have you tried resetting the plug on the driver side? Is there a lock setting in the head unit you can mess with? I know the windows have a trick to reset them. You might want to try that.

 

Resetting as in unplug and plug in? Definitely have done that but unsure if there's a lock setting to reset computer wise.
My truck is very stock so not features on the head unit (I don't have remote locking).

I'll Google some more to see if I can reset the BCM.

 

Did you try the window reset trick?

 

Lock closely at the relay wiring to the door actuators. Power is always available to actuators. Depending on selection, relay completes the circuit to ground in order to lock/unlock by changing direction of power to actuators.
Driver's side and Passenger's side door lock/unlock switch mate before output from Main Body ECU.
My guesstimate is your Driver's side door unlock switch is misbehaving.

 

This exact thing happened to a buddy of mine. Toyota replaced the BCM but the issue still occurred. They ended up buying the truck back because they couldn’t figure it out. It was a 21 Pro

 

Detach the Driver's door lock panel from the door panel.
Remove the connector to the switch panel (kinda tricky, it has a locking tab)
With jumper wire jump 2 to 1 (lock) then 8 to 1 (unlock) if it works fine you have a bad driver's switch panel.

 

Thanks.

Ive tried jumping the wires - it works. Only on passenger side though. Basically the same operation as when the switch is plugged in. Still nothing on driver side.

Appreciate the help so far.

 

Observations so far-

Window trick will set door locks to lock (then unlock automatically) if door is open. Keeping in mind only the passenger lock is doing it.

If I unplug the connector to try jumper this resets that setting.

If I move the driver lock on the door handle while sitting inside truck, I hear something like a relay clicking too. So the vehicle must recognize the actuator movements etc.

Bench tested the old OEM actuator that came out and it works! Must be wiring ?

Baffled. I feel a trip to the dealer coming on.

 

Guys I figured it out.

the black wire (one of the two main pins) on the latch is broken somewhere.

pulled the entire door apart and continuity tested the lot. Unreal luck.

 

Good news. Are you going to try a bridge test? There is a nice chase between the driver's footwell and passenger's footwell that you can run a wire through.

 

Yeah so after I couldn't get my multimeter to beep on the black wire I did run a jumper to bridge the gap. (From actuator to LH footwell plug).

Now if I use the button on the door both locks work properly.

But; If I turn the key in the door only the driver door unlocks. The latch powers but the passenger side won't. So I assume there are other broken wires in the LH harness... position sensors maybe?

I am assuming this proves it's the harness and not anything else. Seems crazy the harness is already broken, though. I couldn't find continuity on the really thin wires so it's gotta be.

May just buy a new one instead of pulling wires. I once re-wired an e30 bmw from footwell to trunk and it took 2 weeks!

 

Cycle the key 2x's in the lock. Once only unlocks the driver door, twice unlocks the passenger door.

 

I would if I hadn't put it entirely back together!

Waiting for the next nice day and I'll fix the entire thing. Great call. I bet it works too.

 

You were correct on the double unlock turn! Pulled a new wire through the door today, hands battered, but all works now. Soldered it in, re-wrapped. Hopefully it endures better than the last one!

 

Glad I could help!