I've been having this problem for a few years now since I bought the Prelude but I fixed the problem by just removing the power door lock fuse and locking the doors manually. I am now doing a somewhat overhaul on the Prelude (which is why as of late you've been seeing a lot of threads posted by me)and want to tackle this problem before I install an alarm system. The problem is that once the power lock fuse is in place the doors will lock and unlock on both sides randomly, I can have the car parked and it will do this constantly. I first noticed the problem when standing outside of my car one day to hear the locks going on and off then it got to the point where I got annoyed by it cause it would happen while driving the car so I pulled the fuse. This happens whether the door is already unlock or locked, it will unlock itself then lock sometimes lock again then lock then unlock. The frequency/consistency of unlock/locks is completely random. Where should I start to diagnose this problem? I don't want to replace parts that don't need to be replaced.

It is either the driver or passenger side actuator (Not sure if the passenger side controls both if the switch is hit on the passenger side cause I have been without power locks for a few years now)
The power lock control unit or one of the switches itself on the door panel (once again not sure if driver and passenger).

 

Sounds like a short somewhere. I actually have this problem too from the previous owner who did a hack job on the alarm install. I pulled the alarm system out to replace it (which I still haven't done) and every once in a while the locks will flicker. Do yours actually lock and unlock or does it just sound like it's trying to? Mine don't actually move, but you can hear it trying. If I fidget around with the wires down by the fuse box I can usually get it to stop, so I know mine is a short, I just haven't bothered to trace it down yet.

 

It actually unlocks and locks. When I had the fuse in, sometimes I'll go inside the store and come back to find my car unlocked then the next it's locked. While the fuse is in, I NEVER leave my car running in case it attempts to lock me out cause sometimes it'll lock then try to relock it self constantly and maybe an unlock, it's usually random. Just a heads up this problem didn't occur till about a year of owning the car, never had a problem before.

 

It's most likely a short. Just in case, do you have an aftermarket alarm?

 

definately a short. check where your alarm is installed (door locks are splices into them) thats where it would be most likely

 

To the edited question, Yes. The passenger side lock controls both doors.

At least, in 5Gs, that's how it works.

 

My beater car does this as well sometimes, and i can sympathize with you on how annoying it is. Mine is a fickle bitch however and always stops when i attempt to find the problem. I think you will have an easy time finding the short if you just look for where the alarm was spliced in.

 

Sounds like he hasn't installed an alarm system, so the short is somewhere in a stock harness. He said he wanted to tackle this problem "before" he installs an alarm.

 

Correct, so far that I know of no alarm system was installed on this car by the previous owner. Ruling out the alarm system theory what could be causing this?

 

 

I'll pull of my door panels sometime today or during this week and try to trace the harness down to find a short. So you don't think it can be anything else? What are the symptoms of a bad actuator and control module?

 

Today I investigated the power lock problem a bit, put the fuse in and plugged the harness to the power lock switch on both sides. I had them unplugged both harness plugs for the power lock switches on both sides as a precaution, funny thing is... the power locks doesn't work at all, I don't get any response from either side. I used the proper fuse, still nothing. Weird?

I looked at the under dash fuse box and found a red wire coming out of the panel that is cut. I wasn't able to get any pictures cause my phone died, will get some tomorrow to see if anyone has an idea of what it may be.

This is the first time I had the fuse and door lock switches plugged up in over a year since it started and now I get no response.

 

I don't know about your fuse problem but I had the same problem with the door lock on my 2001 accord v6 going off every time I closed the door, manually pressing the door switch on the door jamb verified it was repeatable. I first replaced the door lock, did not fix it, not directly anyways. I ended up replacing every component on the door, including the latch mechanism that actually physically grabs the giant door U bolt on the jamb on the frame as well as the lesser known micro switch assembly that connects to the outside door key cylinder. I also suspected the single wire which feeds and completes the circuit for the door switch at the jamb. replacing everything fixed my problem. 3 years later after I fixed it there is still no more intermittent doors locking by themselves but the micro switch on the front passenger side I suspect is now dead because when put in the key on the passenger door outside to command the car to unlock all doors, it worked a few time for a while and now it's completely not working, which points to a dead switch for the key cylinder. that switch is what the car uses to know that you have turned the key. so my advice is try first replacing the switch on the cylinder before you replace the actuator. if replacing both keep going, it is definitely an electrical device malfunction likely due to a worn out part or the weatherseal is gone and the switch has corroded because the passenger door is hardly ever used with a key. my intermittent door lock problem has been fixed for 3 years since I replace all electrical components tied to the front door mechanism