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).
|