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In the past, most cars had door locks that you had to operate manually. Obviously, that’s no longer the case since nearly all modern vehicles have power door locks operated by actuators.

A door lock actuator is basically a reversible motor (or a solenoid on some vehicles) with gears that operate the door lock. The motor reverses direction so that when you press the switch to unlock the doors, the lock moves in one direction. Then when you press the switch to lock the doors, the lock moves in the opposite direction.

Typically, on older vehicles, when you press the door lock switch, power flows through a relay to the door lock actuator. On most new vehicles, however, when you press the lock switch, a signal is sent to a control module (usually the body control module). The module then supplies the power to the actuator to unlock the door.

car door lock actuator
A door lock actuator is basically a reversible motor (or a solenoid on some vehicles) with gears that operate the door lock.

The concept of a door lock actuator works great—until it doesn’t. When the actuator fails (or starts to fail), you’ll likely notice one or more symptoms that make your daily commute less pleasant.

Symptoms of a Faulty Door Lock Actuator

One thing to remember is that there’s an actuator at each door. That means a faulty actuator will only affect a single lock.

If none of the locks work, the problem lies elsewhere.

With that in mind, the most common symptoms of a faulty door lock actuator include:

Power Door Lock Doesn’t Work

A single bad door lock actuator can prevent one of your car’s power door locks from working. You’ll still be able to operate the lock manually, but the power function will not work.

Power Door Lock Operates Erratically

In some instances, a bad actuator may cause the door lock to behave erratically—locking or unlocking when it should not.

car door lock wiring diagram

Strange Noises When Operating the Power Lock

A door lock actuator that’s on its way out may make a clunking, clicking, or grinding noise during operation.

Sluggish Operation From the Door Lock

In some instances, a weak door lock actuator may still be able to operate the door lock, but operation may be sluggish and/or intermittent.

Door Lock Actuator Troubleshooting

In most cases, if only one power door lock isn’t working, the problem is either the door lock switch or the door lock actuator—though the issue could be a less-common circuit problem as well.

One way you can narrow down the list of possible causes is by checking whether there’s power to the actuator. If power is reaching the actuator, but the power lock doesn’t work, the actuator is probably faulty.

You can verify whether power is present by using a digital multimeter (DMM). Here’s how it’s done:

Note: The following are general guidelines for educational and entertainment purposes only. Consult your vehicle’s factory information for specific repair instructions and recommended safety procedures.

1. Put on your safety glasses.
2. Remove the door panel to access the door lock actuator.
3. Visually inspect the actuator to ensure it’s mounted properly and the linkage is not binding.

door lock actuator and linkage
Visually inspect the door lock actuator and linkage.

4. Remove the actuator connector.
5. Set your meter to the 20 volts DC scale.
6. Connect the negative meter lead to a good ground. Then connect the positive meter lead to one of the power feed terminals on the harness side of the actuator connector.

Note: If your vehicle has more than two wires going to the actuator, you will need to consult a wiring diagram in a repair manual to determine which are the feed wires.

Also, you can use jumper wires (or a Power Probe) to apply 12 volts directly to the actuator. However, because the actuator is often difficult to get to, it’s usually easier to check for power to the actuator.

Here is a video demonstrating the jumper wire method:

What to Do if You Have a Bad Door Lock Actuator

If you’re dealing with a bad door lock actuator, you can do one of two things: Live with the problem (and operate the lock manually) or move forward with replacing the actuator.

Replacing the actuator will cost you money, but it will also make your vehicle more convenient.

Products Mentioned in this Guide

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Josh Byers

im having problems with wiring i believe cause they work or if i use the ulfob more then a few times in a row it hrows weaker and at the same time im having rear speaker issues i drive 1 1998 monte carlo

CarParts.com

Hi Josh,

Have you tried replacing the battery in the fob?

Josh Byers

yes i have but at same time im having problems wih rear speakers as well

CarParts.com

The speakers are likely an unrelated issue.

Bill

Sliding door actuator on 2001 Eurovan works when tested directly off battery but not when installed, even though probe light shows power to actuator.

CarParts.com

Hello,

Have you checked the ground side of the circuit?

Bill

Yes, Originally I did not have ground to the actuator and I was able to get it by cleaning the switch that transfers power to the sliding door.

CarParts.com

Is it working now?

Bill

I double checked for ground and I found the problem. I had continuity from the spring loaded switch to the actuator when the door was open. The contacts between the door and frame seemed to be good because I had power to the actuator through the positive ones. But when I closed the door and probed the connection to the actuator I couldn’t get any light. Anyway, I took switch apart again and saw that the contact strip that the spring loaded switch road on had worn through near the end . So I had ground until I closed the door and then lost it. Anyway I’ve bent the contact some so it works now and will start saving up for a new switch.
It will be so nice to not have to walk around the van to manually lock that one door, I must be getting lazy. Thanks, for your help.

Bill

Yes, and cleaned the switch that transfers power to the sliding door.

Om Prakash

In Honda civic, after I overhauled my power lock by changing 3 actuators, I’ve lost power and pick-up. Please comment.

CarParts.com

Hello,

Do you mean the engine now lacks power? If so, the issue is probably unrelated to the actuator replacement.

Ray Talbert

Hey, the power locks in my 2004 CTS Cadillac are not working. I’m trying to order parts. Why does engine size make a difference?

CarParts.com

Hello Ray,

Engine size generally will not matter when ordering door lock actuators.

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