lost unlocking function on lock module.

[flux3d]

Since i got 10719 I've had the door lock module unplugged, mainly because it always failed to lock or unlock the passenger side door and protect against potentially being locked out of the car. However today I stripped down the door and adjusted the locking mechanism so that it locks and unlocks smoothly as intended. However, plugging in the door lock module (which seemed to work perfectly previously ) the solenoid fires on both doors to lock them, but refuses to reverse it's action to unlock them.

My initial thought is that half of the module (the unlocking side) has failed somehow, leaving the locking side intact.

Is this something anyone else has experienced? I know there are a couple of documented ways to modify the door lock module to reduce the risk of the relays sticking and frying the solonoids. Are these a reliable solution to the problem or would people recommend the actuators route?

[Bitsyncmaster]

From what I remember, the solenoids have two coils. One is for lock the other for unlock. The door lock module has two relays, one for lock other for unlock. If your open the module and press one relay at a time that would test the solenoid wiring if it works or not.

If it works, you can watch the relays to see if they close when one door lock switch is pressed.

[DMCMW Dave]

Each door has a lock and unlock switch contact. Check those too.

[DMC5180]

In addition what is mentioned above, I've seen the door harness connector under the T-panel have a burned/corroded terminals on one leg of the two powered open/close wires. Simple continuity checks of the solenoid harness connector and the DLM harness connector should be able to verify the wiring circuit.

[David T]

In addition what is mentioned above, I've seen the door harness connector under the T-panel have a burned/corroded terminals on one leg of the two powered open/close wires. Simple continuity checks of the solenoid harness connector and the DLM harness connector should be able to verify the wiring circuit.

It can also be possible the coils are burnt in the solenoids. Cut a 10 amp in-line fuse into the big red wire going to the door lock module. The circuit breaker will never pop, it is way too big and acts too slow. For the Central Locking System to function you must have both doors adjusted according to the manual and everything "just so". If both doors are not in 2nd locking position it should not lock. If you have forced it to lock it may not unlock.

[Elvis]

plus - the fuel pump cut-off (inertia) switch can be melted inside which leads to the same problem.

Check the schematic.

[flux3d]

Elvis you may just have it right there. I always lift up the plunger on the inertia switch when is parked in the garage as a second level of theft protection. Maybe that's all it is. I'll have to go check. Thanks. :)

[Bitsyncmaster]

Elvis you may just have it right there. I always lift up the plunger on the inertia switch when is parked in the garage as a second level of theft protection. Maybe that's all it is. I'll have to go check. Thanks. :)

Lifting the plunger should lock the doors. Not good to do that with the door open.

[David T]

Lifting the plunger should lock the doors. Not good to do that with the door open.

In the event of an accident the inertia switch is supposed to unlock the doors. The inertia switch was the subject of a recall so you need to make sure it was complied with. I have seen a lot of "creative" wiring in that area usually because it also is part of the fuel pump circuit. Make sure the inertia switch has a splotch of white paint on it and is mounted to the side of the footwell NOT the Lambda counter.

[DMCMW Dave]

Lifting the plunger should lock the doors. Not good to do that with the door open.

Lifting the plunger unlocks the doors.

[Bitsyncmaster]

Lifting the plunger unlocks the doors.

Brain freeze.:bawling:

[flux3d]

Good point about the plunger unlocking the doors. As the lock module has been unplugged since I got the car it was never a problem. Putting the plunger back down and plugging everything back in the central locking works flawlessly. I now have working central locking for the first time since I got the car. Result! However, strange that with the plunger up the system would lock the doors, not open them. Odd. No problems with the inertia switch as far as I can see.

So, with the old system working well how can I keep it this way. Maybe an in line fuse on the door lock module?

[David T]

Good point about the plunger unlocking the doors. As the lock module has been unplugged since I got the car it was never a problem. Putting the plunger back down and plugging everything back in the central locking works flawlessly. I now have working central locking for the first time since I got the car. Result! However, strange that with the plunger up the system would lock the doors, not open them. Odd. No problems with the inertia switch as far as I can see.

So, with the old system working well how can I keep it this way. Maybe an in line fuse on the door lock module?

If the inertia switch LOCKS the doors that can be a problem especially in the event of an accident. Something somewhere got crossed and should be fixed. Till then disconnect the big red wire from the circuit breaker or cut an in-line fuse into it.

[DMC5180]

Good point about the plunger unlocking the doors. As the lock module has been unplugged since I got the car it was never a problem. Putting the plunger back down and plugging everything back in the central locking works flawlessly. I now have working central locking for the first time since I got the car. Result! However, strange that with the plunger up the system would lock the doors, not open them. Odd. No problems with the inertia switch as far as I can see.

So, with the old system working well how can I keep it this way. Maybe an in line fuse on the door lock module?

Did you actually test the system sitting in the car with doors closed and locked, then pull the inertia plunger up with the key ON? It's been mentioned before not to operate the lock system with the doors open. It can cause problems. I would have difficulty reaching the inertia plunger sitting in the driver seat, but I could do it from the passenger side leaning over the console.

[Elvis]

Good point about the plunger unlocking the doors. As the lock module has been unplugged since I got the car it was never a problem. Putting the plunger back down and plugging everything back in the central locking works flawlessly. I now have working central locking for the first time since I got the car. Result! However, strange that with the plunger up the system would lock the doors, not open them. Odd. No problems with the inertia switch as far as I can see.

So, with the old system working well how can I keep it this way. Maybe an in line fuse on the door lock module?


1. YES to the fuse, yes yes yes yes !!!!
I've been posting this for years. YES !!!! a 10 A fuse !!!!

again :

YES YES YES 10 A fuse!!!


2. if you guys are able to read a simple schematic you will recognize, that in case of an emergency the
inertia switch UNLOCKS the doors !!!!
Once the UNLOCK signal is given to the circuit, the capacitors are discharged and will only be charged again
when you lock the doors.
It's the same with one door locken and the other unlocked - the circuit does not work in this situation.
Is this case wanted ? Probably not, but a late 70s cheap circuit and with a good working power lock system
this does not matter at all.

So again - this is a safety feature - automatically unlocking in case of an accident !

[flux3d]

Thanks Elvis. Yes i can read a simple schematic, i just hadn't realised the inertia switch lead to this function in the lock module. As i explained I've always had the whole system unplugged since 2012 when i got the car. My usual proceedure was to lift the plunger from outside before shutting the doors and locking them. I'll have to try locking the doors and pulling the plunger up with the key in to see what it does. Oh and Yeah i know about not locking the doors while they're open. If i need to (like when i did the door lock adjustment ) I swing the latch over with a screwdriver. :)

[flux3d]

Yep. All works as it should. One thing i did wonder. With the plunger of the inertia switch pulled up you can shut the door and activate the central locking just once to lock the doors. After this single "pulse" you're back to manual use until you push the plunger down. But does this mean that by pulling up the inertia switch the draw the OEM system puts on the battery is also deactivated? If so it's a good procedure for storage.protects from theft as well. Like a basic engine immobiliser. :)

[Bitsyncmaster]

Yep. All works as it should. One thing i did wonder. With the plunger of the inertia switch pulled up you can shut the door and activate the central locking just once to lock the doors. After this single "pulse" you're back to manual use until you push the plunger down. But does this mean that by pulling up the inertia switch the draw the OEM system puts on the battery is also deactivated? If so it's a good procedure for storage.protects from theft as well. Like a basic engine immobiliser. :)

No the current draw would be the same. So it would not help to pull the plunger.

[flux3d]

Ah Thanks Dave. Shame, but at least it still acts as a kind of immobiliser.

[David T]

Ah Thanks Dave. Shame, but at least it still acts as a kind of immobiliser.

I do not recommend using the inertia switch as a theft deterrent device. It was not made for repeated use. A better theft deterrent is a battery master switch since it is not common knowledge where it or the battery is. To make it even more secure there are battery switches that operate with a removable key.

[flux3d]

Thanks David. Sounds like a good idea. I did wonder about the inertia switch.better to not stress it too much. After all a non working fuel pump on a drive isn't exactly a good idea. :)