So thanks to the awesome help of TiMi I have been able to identify a very odd, probably electrical problem with my central locking.

While originally I thought it was the drivers door actuator, having tried a different actuator, the issue was still occurring. I realised this when, while testing the new actuator, it just suddenly stopped working. The lock rod would physically move but the actuator would not fire when it was moved. I can move the lock rod as much as I want but the actuator won't fire until about 10-20 seconds later when it just starts firing again and then works seamlessly for a little while until it stops again.

I confirmed it is definitely not two faulty actuators because during this period of not firing the new actuator, if I quickly swap the wiring plug to the old actuator and the old one doesn't fire either, until about 10-20 seconds then it starts working flawlessly again.

So I know it isn't the driver's actuator, I'm thinking maybe is it maybe a different actuator? I moved to the passenger door and started locking that with and without the key. Same symptoms, works sometimes, then it just goes totally dead, completely irrespective of the position of the locks, whether the doors are open or closed, or even if the engine is on or off. Half the time my actuators all fire, half the time none of them fire.

What could be causing this? While in a period of dead actuators, if I open the drivers door and try to hit the lock button on the remote, the horn does sound so it knows the door is open, all the courtesy lights work, and if I use the key in the lock while the actuators don't work, it does lock that door, but none of the others.

What could the problem possibly be? :(

So, bit of an update. Been trying lots of things to sus out its behaviour, also noticed this pecularity:

As many of you presumably know, the doors will not lock when the key is in the ignition. The drivers door locks, then the actuator fires to unlock it immediately afterwards until you remove the key.
Surprisingly, this functionality still works even when none of the actuators will work by any other means. That is, while it is going through its period of no actuator function, if I press the remote buttons, turn the key or manually push the interior lock switch, that actuator will not activate, nor will any of the other doors. However, if I then put the key in the ignition and flick the drivers door switch to locked, the actuator will fire to unlock it. Take the key back out, the whole system is dead again.

I think it's safe to say I've ruled out the actuator in the drivers door and I don't see how the actuator in the other doors would affect the drivers door and they all work when the drivers door does so I'd say the actuators are fine. But all the other electrics in the door are fine and clearly you can still get a signal to the actuator even when it's in dodgy mode so I don't think it would be the loom connection either. So what the **** is this!? I think I may need to just spend a cool day ripping all the doors off and using the replacement loom, actuators and rods to just totally replace everything in the doors. If it still does it... I'm ****ed.

trace the drivers door loom back and swap the plugs on the spare loom with the ones plugged into everything in your door, see if it works on the other loom.
just run it outside the door temporarily to test, as its a pain to get to all the spots its clipped in to when fitted (for those of us with fat fingers at least)

So, bit of an update. Been trying lots of things to sus out its behaviour, also noticed this pecularity:

As many of you presumably know, the doors will not lock when the key is in the ignition. The drivers door locks, then the actuator fires to unlock it immediately afterwards until you remove the key.
Surprisingly, this functionality still works even when none of the actuators will work by any other means. That is, while it is going through its period of no actuator function, if I press the remote buttons, turn the key or manually push the interior lock switch, that actuator will not activate, nor will any of the other doors. However, if I then put the key in the ignition and flick the drivers door switch to locked, the actuator will fire to unlock it. Take the key back out, the whole system is dead again.

I think it's safe to say I've ruled out the actuator in the drivers door and I don't see how the actuator in the other doors would affect the drivers door and they all work when the drivers door does so I'd say the actuators are fine. But all the other electrics in the door are fine and clearly you can still get a signal to the actuator even when it's in dodgy mode so I don't think it would be the loom connection either. So what the **** is this!? I think I may need to just spend a cool day ripping all the doors off and using the replacement loom, actuators and rods to just totally replace everything in the doors. If it still does it... I'm ****ed.

or maybe its gremlins somewhere else in the car electrics O_O

It's cooled down outside now which makes this extremely hard to diagnose as the hotter it is, the more frequent this happens. When it was 37 and in the sun this arvo it was working for 20 seconds, not working for 20 seconds, working for a minute, not working etc. - now though because it's mid 20's and night, it barely ever does it and not for as long, I'll drain the battery if I keep testing. Unfortunately no Dynamat in the doors for me tomorrow, but I'll continue to try to fix this issue because there is no way I'm paying $600 to Mitsubishi to do it.

But yeah the fact it still unlocks itself with the key in the ignition has me stumped. I think it might be gremlins :(

Nobody got any ideas? Might need to replace all the loom and all the actuators and reassess. MR SPL suggested it might be the body control module... I have absolutely no idea what/where that is or how to handle it. :(

Nobody got any ideas? Might need to replace all the loom and all the actuators and reassess. MR SPL suggested it might be the body control module... I have absolutely no idea what/where that is or how to handle it. :(

The body control module is located behind the dash - on the drivers side - above the fuse box. You won't need to take your dash out to get access to it. You do need to take out the bottom drivers footwell panel. Its a large (8cmX8cm approx.) square box hanging by a C shaped bracket tightened onto the dash rail with two bolts. It'll have about three sets of harness' with heaps of cables coming out the back of it. Pull out the connectors and inspect them.

Mr.SPL may well be right. The BEM does control the locking system as well (incl. door and ignition) so if it was faulty then it could cause these problems. I'd definitely first try and rule out the door components being faulty, before planning to replace the BEM. Only because the BEM is locked to the ecu. I'm quite certain that if you want to replace the BEM then you either a) need to get a new ecu and ignition barrel to pair with the new BEM or b) have your ecu's immobilizer unlocked by Steve Knight (SKR) and matched to a new BEM. c) Alternatively if you found a KJ Series II GTV wreck then you could just straight swap out the ecu, ignition barrel and bem. Either way it could be a costly exercise so do everything to eliminate any other potential reason for the locks behaving in this way. Although you have a GTV - your door looms should be the same as a KJ Series II Verada and actuators are the same across magna's & verada's. So head down the wreckers or find some good AMC friends and test fit other actuators & looms to see if that fixes anything. Be sure to check all connections/harness/wiring to see if any cables are severed, damaged, dirty or have been exposed to water.

Good luck mate. Hope you finally sort this issue out!

Or, you could get the ECU and BEM from a wreck and just get new keys cut for your car and programme them into your new ECU

The body control module is located behind the dash - on the drivers side - above the fuse box. You won't need to take your dash out to get access to it. You do need to take out the bottom drivers footwell panel. Its a large (8cmX8cm approx.) square box hanging by a C shaped bracket tightened onto the dash rail with two bolts. It'll have about three sets of harness' with heaps of cables coming out the back of it. Pull out the connectors and inspect them.

Mr.SPL may well be right. The BEM does control the locking system as well (incl. door and ignition) so if it was faulty then it could cause these problems. I'd definitely first try and rule out the door components being faulty, before planning to replace the BEM. Only because the BEM is locked to the ecu. I'm quite certain that if you want to replace the BEM then you either a) need to get a new ecu and ignition barrel to pair with the new BEM or b) have your ecu's immobilizer unlocked by Steve Knight (SKR) and matched to a new BEM. c) Alternatively if you found a KJ Series II GTV wreck then you could just straight swap out the ecu, ignition barrel and bem. Either way it could be a costly exercise so do everything to eliminate any other potential reason for the locks behaving in this way. Although you have a GTV - your door looms should be the same as a KJ Series II Verada and actuators are the same across magna's & verada's. So head down the wreckers or find some good AMC friends and test fit other actuators & looms to see if that fixes anything. Be sure to check all connections/harness/wiring to see if any cables are severed, damaged, dirty or have been exposed to water.

Good luck mate. Hope you finally sort this issue out!

Thanks for the very informative post mate, although you've sort of confirmed my fears. If this is indeed the BEM/ECU I will probably just ignore the issue because quite frankly I don't think it's worth the effort and cost. But luckily I already have all spare actuators, rods and loom from TiMi to try so that'll be this week's ****ed project to have a go at, heh.

We'll see how I go. Will report back once all the door actuators and loom are replaced. To that end though, I've never actually pulled the door apart sufficiently to actually get through to remove and replace the actuators, I only got as far as plugging in the new actuator outside the door to test it. I can see several bolts but it looks like there's more to it than that. Is removing the metal frame of the door a difficult job?

While ignoring the Bem for now will work, it's uncertain how long you have before it packs up completely and stops you either getting on your car or starting it! Worth trying what you can before it happens. I have kj Bem at home and possibly ecu also

*groan*
Alright we'll see where I'm at by next week I guess.

If it helps - here's a pic of where the BEM is located. You do not need to take out the dash to get to it but you do need to remove the panel in the footwell on the drivers side. You may want to remove the drivers seat for better access and comfort. You'll probably need to remove the drivers side fuse box, drivers air vent and electric mirror switches for better access and get the cables out of the way.

http://desmond.imageshack.us/Himg851/scaled.php?server=851&filename=bemlocation.jpg&res=medium

Spoke to the service department today, explained I confirmed it was not the driver's actuator and he was surprised and stated if not that it would be an electrical connection somewhere or the BEM. He said the BEM was I think $239, but then when I asked wouldn't that need new keys and everything he's like "...ohhh... yeah maybe. That could be very expensive."

Uh oh. >.<

Pleaseee be the wiring >.<

As said above - if you're sure its the BEM then search high and low for a GTV(i). The GTV(i) was around for about 3 years before the final TW GTVi (black & awd - very hot looking car) was released so there should be a wreck somewhere. You may need to look interstate. I know a few members here have wrecked GTV's - I think MrSPL recently dismantled one and some time ago Ange71 did the same. Alternatively, depending on price, you could buy a GTV wreck - like this one in NSW (http://www.pickles.com.au/damaged/item/-/details/11-02--Mitsubishi--Verada/1002250439) and part it out. I know you'd get very good money for the nardi gear, black leather & interior trim, blackout dash, gps gear, 5sp gearbox and engine plus the usual array of Verada goodies that everyone loves! I dare say there are a few eyes on that GTV though...

The GTV was similar to the VRX/Sports with power (Basically shared VRX exhaust, suspension and 240km limited ecu) so maybe you can use the ecu, bem & ignition barrel out of them? There's plenty of Series II VRX's being dismantled.

check the plugs aren't loose, and if you have some electrical contact cleaner, disconnect the battery and spray it on the ends of the loom connectors and wait for it to dry completely before plugging everything back in. (leaving the plugs wet can cause corrosion)