Dodge Repair: Door lock question: 06 Ram

Question
I have 2006 Dodge Ram 1500 with a few small issues. The one that has me stumped is the 3 passenger doors will lock from the button on the key, the driver's side door, and the passenger side door, but will not unlock. The driver's door unlocks and locks normally from all of the unlock/lock switches. On the locks that won't unlock, I put my ear close to the doors where the actuator is and it will make a noise like its "trying" to unlock but it doesn't push the lock up.
Looking online, the common problems were either 1) 3 broken actuators, 2)frayed wires from where the door opens and closes
I put in a brand new actuator on the front passenger door, and it didn't change.

I then pulled the wiring out of the door and inspected it for any frayed wires and then bought a multimeter and discovered how to inspect continuity, and it did have it for the section in the door.

I also looked at the fuses to see if there was a obvious "unlock passenger door" fuse that was blown, but I see only one that said anything about locks and it was fine.


So-reading more about it online, is there a way to test with a multimeter if the actuator "solenoid"(is that the right term? Is that the electrical component that controls the motor that pushes the lock/unlock rod up and down?) is getting enough power? 12V? Is that correct? I've learned alot in the past couple days and its great, just curious about how it works. I figured maybe the actuator motor isn't getting enough "juice" to unlock.

Going to continue researching on what it could be, it seems so strange that it is the 3 passenger doors AND from all the buttons/switches that unlock it

Thanks all for any help!

Answer
Hi Caleb,
Given your observation of the "action" soundings when you request locking, I
would
not suspect a wiring problem. Rather I would wonder about the effort required by the door lock motors to actuate the mechanical parts that they service. It may be that lubricating the lock cylinders and other components that the motors move using powdered graphite grease will improve the actuation of the various door locks. You might remove the door panels to observe the various parts that are moved when you try the locks and then lubricate them.
The system uses 12v throughout so the other possibility may be that the battery voltage is low due to age of the battery. Each motor is equipped with a temperature sensor which shuts off the motor after a few seconds of effort when it is unable to carry out its assigned action. That could happen due to either friction in the mechanism or a too low voltage on the system.
It is a very complex system electrically, but there is some self-diagnostic
capability which can be accessed using a code reader which is capable of questioning the body computer for any faults (codes are four digit numbers preceded by a B). That would be another thing to try. Let me know if you get any such fault codes.
Roland