hey guys, been having trouble with my drivers side power door lock on my mazda b4000.
Passenger side works perfect(with remote and door switches), initially i thought it was a blown fuse, but the fuse diagram i found online showed a single fuse for power locks and not a separate for drivers and passengers. next i thought it may be a relay, but it seems unlikely because in that case the lock and unlock relays would have to both have gone at the same time. next my thought was that the door lock actuator itself has gone bad, so i ordered a new one, and before taking the old one out i took the plug off, and plugged it into the new unit aaaaand it did not actuate the new unit either. I'm stumped, is there something I'm missing? was working fine until a couple of months ago just getting around to it now. ( i just tried to check the power cable with my volt meter but its decided to act up so ill have to do that later when i fix it or get a new one)

Any help is appreciated.
Thank you!

 

The Lock relay function does both doors with Fob, but drivers door has a separate unlock relay, just FYI, probably not the issue

And unfortunately there is no direct wiring between the door actuators and switches

In 2005 the door switch or Fob sends a signal to Smart Junction Box(SJB) in the passenger side kick panel, and it then activates the relays

Door lock actuators work the same as power windows, BOTH wires at the actuator "motor" should test as good GROUNDS, that is their "at rest" state
The relays in the SJB are the source if those grounds
When you unLock only 1 of the wires is disconnected from it's ground and connected to 12volts
To Lock, the other wire is connected to 12volts
So test if BOTH wires are good grounds, 0 ohms to cab metal if not then wire issue, probably in the door jamb boot, or at SJB connectors

 

Hey Ron, thanks again for your knowledge!
I finally had a chance today to test the wires and indeed one side of the connector is not grounded, the other shows almost no resistance to cab metal. everything under the door jamb boot seems to be in tact and id rather not tear that bundle apart if i dont have to, and it seems like an unlikely source of the issue since everything else on the door works fine. would you happen to know any way i can troubleshoot the SJB? might be easiest bet to just ground the wire that's not working and live with just one of the functions working.

Thanks again Ron, very helpful info.

 

No, can say I have ever come across the schematic for Ranger SJB, or any Ford SJB

Page 2 below has wires label for door locks, but not very clear on whats for what i.e. actuator or switch, but wire color might help you on that
You could test the wire without the ground to see if it has continuity back to the SJB, if so problem is in the SJB

This is a picture of the surface mounted relays in the SJB: https://www.therangerstation.com/tec..._project-9.jpg
None are labelled so sure what you can do as far as trouble shooting

There were only 2 models of SJBs used in Rangers, with Keyless entry(fobs) and without keyless entry
So not hard to find use one