No voltage to driver's side lock actuator? Door will lock, but not unlock.

Hi all! New Taco owner - 2013 TRD Sport Double Cab Auto - excited to find a forum like this.

Symptoms:
Driver's side front door WILL LOCK, but WILL NOT unlock electronically (via FOB or power lock rocker-switch inside the cab). All the other doors locks are behaving normally via both methods. I have to use the key in the lock cylinder from outside, and the manual lock switch from inside to get out of the vehicle.

First attempt:
I replaced the lock actuator motor. Still not able to power unlock the driver's side front door.

Diagnosis:
I did confirm (by moving the drivers side actuator unit to the passenger side), that the motor/actuator combo is capable of working fine for both lock and unlock.

The passenger side harness is getting some voltage when the door is supposed to unlock, but it doesn't seem that the drivers side is getting any voltage.

To me, this seems like either I have a short somewhere or I need a new Body ECM

Does anyone have any ideas on next steps?
Thanks so much!
Jeff

 

Just replace the actuator assy.

 

Try this. Key in the ignition and turned off. Open the drivers door. You should hear beeping warning that the key is in the ignition. Manually lock the drivers door. The BCM should unlock the door to prevent you from locking the keys in. If it doesn’t, the most likely thing would be a broken wire in the harness near the hinges. If the BCM does unlock it, you possibly have a switch problem.

 

ARB1977 - the actuator assembly seems like it’s fine because it works great when I swap it to the passenger side.

MuddinFun thanks for the suggestion. With key in ignition (off position) and door open I do indeed hear a beeping. When I manually lock the driver door, all the doors except the driver front Successfully unlock. If I then close the door, it sounds like the truck makes two attempts to unlock all doors. But still no budging from the drivers side.

ugh if this is a broken wire (sounds plausible) I bet it is going to be a pita to find and fix.

 

Dukes of Hazzard it!!!

 

These may help:

 

The body ECU is the same as the cab fuse box.

 

Thanks all - current plan is to pull the body ECU and do some continuity testing to check for a wire break.

To ARB1977’s idea of replacing the actuator assembly - can anybody confirm that swapping the drivers side assembly to the passenger side and seeing expected operation is sufficient to rule out the assembly as the problem? As I was thinking about it more last night, I am wondering if the circuit differences between driver and passenger side could make an assembly work fine on the passenger side but not on the drivers side.

 

After getting a good nights sleep and relaxing while drinking my morning coffee, I came to the realization that your problems make no sense at all. The actuators work by applying voltage in 1 direction to lock and reverse polarity on the same wires for unlock. So, there can’t be a broken wire. The actuators are are all wired in parallel, so if other actuators work, the body ECU must be good. Swapping the drivers side actuator to the passenger side confirms that the actuator is good. There’s nothing left.

 

i have replaced 3 of the 4 door lock motors in my truck for stuff like this. 6 dollar part just replace the little motor and i bet it works well.

 

Thanks Muddinfun! Appreciate the consideration.

There is definitely something unique about the drivers front unlock though, because when a key fob unlock is clicked only once, only the drivers side front is unlocked, right? Something in that circuitry has got to be a problem.

nd4spdbh I did replace the motor actually already

 

Oh yeah. I guess I was just blindly looking at all the other actuator wiring. New realization, but not awake enough to consider fine details. So, it would appear the body ECU must be the problem?

 

ok.... this is rather odd.

 

I do have a check engine light on (precious scan showed O2 sensor) and the TRAC OFF Light on. Is there anything tricky with Tacoma’s where if it has a check engine light it won’t allow driver door electronic unlock? That would be weird but worth asking before I dig out this ECU

 

Totally not related.

 

It might be worth checking to see if you have any other codes (ABS & SRS)
Just in case there is a “short” some where, hate to see a new Body ECU go out as soon as it’s plugged in. More than likely, there isn’t, but who knows?

 

TnShooter - good tip. I'll rescan it before putting the new ECU - just popped for one from Ebay since all my checks on the power window switch, actuator, etc looked fine. Only thing that's is clearly wrong is that I'm not getting the necessary voltage from the ECU power connector B-3.

Seems like a bad ECU

 

if it isn’t putting out, then that all it can be?
Hopefully you can pick one up for a reasonable price?

 

How about just removing the B5 #3 (Driver's unlock) and jumper it to the Passenger's Unlock? 2 press FOB unlock, before purchasing a used or new BECU...connector 1H pin 5.

Or from connector IC6 pin 9 removed and jumper'd to 1H pin 5.

 

I suppose that’s worth a try, maybe OP will give it a try?
It’s a work around and wouldn’t cost any money.

Still like to know what is causing the other codes?