Power locks not working

[cleatus12r]

The door lock actuators use a thermal resistor circuit breaker. It's a safety feature to keep kids/dogs/cargo from burning the truck to the ground if the door lock switch is depressed too long. As the temperature of the circuit breaker goes up, so does the resistance. As resistance goes up, the current though the circuit goes down thus minimizing heat created in the circuit in the event of a short or a switch depressed for an excessive amount of time.

Over time, these resistive circuit breakers "wear out" electrically and limit current to the actuator motor windings even under normal (cool) situations. Yes, it is possible to disassemble the actuators and provide a parallel shunt across the circuit breaker but it's not adviseable due to safety reasons.

Unfortunately the only way I know of doing it properly is to replace the entire actuator in each door (which if you have a crewcab truck will cost you plenty).

[rammertide07]

Originally Posted by cleatus12r

The door lock actuators use a thermal resistor circuit breaker. It's a safety feature to keep kids/dogs/cargo from burning the truck to the ground if the door lock switch is depressed too long. As the temperature of the circuit breaker goes up, so does the resistance. As resistance goes up, the current though the circuit goes down thus minimizing heat created in the circuit in the event of a short or a switch depressed for an excessive amount of time.

Over time, these resistive circuit breakers "wear out" electrically and limit current to the actuator motor windings even under normal (cool) situations. Yes, it is possible to disassemble the actuators and provide a parallel shunt across the circuit breaker but it's not adviseable due to safety reasons.

Unfortunately the only way I know of doing it properly is to replace the entire actuator in each door (which if you have a crewcab truck will cost you plenty).

Thanks for the reply Cody. Is this something that would happen to all 4 doors at once? After I replaced the fuse, I was able to get the locks to attempt to actuate. But they all seemed like they wasn't getting enough juice, and each click of the button the juice seemed to decrease a little bit at a time...to all of the door locks.

I'm going to attempt to install a security system and it would be nice to have the door locks operating. Otherwise I wouldn't be worrying about it.

[rammertide07]

Is there a wire I can check to see if it gets voltage when the lock/unlock button is pressed?

[cleatus12r]

The switches control the ground circuit of the lock actuator motors. The common scenario is that the actuators get weaker after the first button press and then begin to do less on subsequent presses.....once you let them rest for a few minutes, you can repeat the process.

It's not hard to test, but the best way to do it is to actually measure current flow through the circuit. Measuring voltage will only test the switches, power, and ground circuits.

It's not uncommon for all of the actuators to take a dump (my 01 CC was the same way). One fails and the others slowly follow until none of them work.

[rammertide07]

Okay, I'll probably get 2 actuators and see if that does the trick. If so, I'll buy the other 2. Thanks for the info Cody.

[rammertide07]

Amazon has them pretty cheap...

Amazon.com: Dorman 746-149 Door Lock Actuator: Automotive

They also have EBP sensor for $76. Gotta get one of those too and tube.