car fuse keeps blowing

[Travis]

I replaced the fuse for my car's power locks last week after they stopped working and I discovered the fuse had blown.  It looks like it did it again. Is there a way to track down where a short or overload might be happening to repeatedly blow that fuse or will I have to take it to a mechanic?

[sokoloff]

Power door locks are solenoids. Solenoids are electromagnets and there's a possible failure mode which might draw more current.

I'd start by observing how the door locks behave. Is there one that's sluggish, different from the others? (Or does one not work at all?) If it does, disconnect that one (means tearing the door panel off; youtube for videos for your car to find the hidden screws and fasteners). If you can find the one that never blows the fuse if disconnected, replace that one (or leave it permanently disconnected). They will disconnect with a releasable connector (typically push a lever somewhere on it and pull it out).

The part itself will be cheap for most cars. I would only get direct-fit parts, but you don't have to buy factory parts. Rockauto is my normal source for things like this, though ebay and amazon are also viable. By "direct fit", I mean don't try to retrofit a generic car stereo store aftermarket actuator. Get something that bolts straight in.

[Travis]

Power door locks are solenoids. Solenoids are electromagnets and there's a possible failure mode which might draw more current.

I'd start by observing how the door locks behave. Is there one that's sluggish, different from the others? (Or does one not work at all?) If it does, disconnect that one (means tearing the door panel off; youtube for videos for your car to find the hidden screws and fasteners). If you can find the one that never blows the fuse if disconnected, replace that one (or leave it permanently disconnected). They will disconnect with a releasable connector (typically push a lever somewhere on it and pull it out).

The part itself will be cheap for most cars. I would only get direct-fit parts, but you don't have to buy factory parts. Rockauto is my normal source for things like this, though ebay and amazon are also viable. By "direct fit", I mean don't try to retrofit a generic car stereo store aftermarket actuator. Get something that bolts straight in.

So far it seems to happen as we get out of the car and try to lock the car using the remote.  If the short is in one of the actuators, could the remote be engaging it and causing the short?

[sokoloff]

Yes, exactly, but it's unlikely the remote's "fault", but rather an actuator fault. (I think you know that, but I'm being extra-explicit.)

You probably also have a button in the car that will operate the locks. You could replace the fuse and cycle the locks from inside the car, watching and listening for any difference in behavior that might tip you off to which actuator is behaving differently (and also figure out about how many cycles until the fuse blows typically). If you have locks where you can operate them manually, you might also try holding the lock unlocked while forcing the power lock to lock the car (goal is to put some additional load on the lock mechanism, so be sensible, but also to feel if any of them lock more or less forcefully).

Ultimately, you're going to have to remove a door panel (or several) and that's a task I dislike doing because of how fiddly it can be to remove them without breaking any of the plastic fasteners.

[HipGnosis]

So far it seems to happen as we get out of the car and try to lock the car using the remote.  If the short is in one of the actuators, could the remote be engaging it and causing the short?

The remote is locking all of the doors, by engaging all of the actuators, at the same time.   That means the remote is working.  The remote is triggering the short, but one of the lock actuators is the (most probable) cause/source of the short.
Replace the fuse. 
Unlock each door by it's individual unlock button, checking the fuse after each door.
If you get them all unlocked and the fuse doesn't blow; lock each door by it's lock button, checking the fuse after each one.
Replace (or disconnect) the actuator that blows the fuse.
You may be able to swap actuators - say drivers door and passengers door.

[sequoia]

Check wires from the body of the car to the door. The door open and close several thousand times, and there is a good chance you have a wire that are pinched, and then worn down and cause a short. The wires should be covered with some rubber protector to protect from element - you can see these when you open the door, you will see some rubber piping from the body to the door. Good luck!