SLK will not lock

[MW]

SLK 2004. Went out today and all was normal. Came home and tried to lock the car on the fob. The light flashes 3 times but nothing happens. Car starts as normal. Normally it flashes once. Tried both fobs and exactly the same. Bit desperate. I thought the key that starts the engine would lock the door but it does not. Is that usual? I thought I could manually lock it.
Any ideas much appreciated.

 

[AMGeed]

Does the metal blade emergency key not unlock/lock the drivers door?
It slides out from the top of the fob.

 

[MW]

Is this the same as the 'flick out' key' that starts the engine? It opens locks the boot but not the doors. Not sure if it has been changed.
The doors and everything open and close on the internal door lock button.

 

[AMGeed]

If that flip out key locks/unlocks the boot, it should do the drivers door as well?

 

[MW]

I thought that but it does not. Odd thing is, it all works on the interior door lock dash button.

 

[Brian23]

Hi, it could be the PSE Pump in the boot. The way it sits in it's proctective covering, it fills up with water and the circuit board rots and then there are breaks in the circuit. You can extend the wires and sit it upside down so that it stops this happening again after you have repaired it.

 

[MW]

Is a repair possible?

 

[MW]

If it locks on the internal dash button, can the PSE pump still be at fault. If it is, what is operating the full locking system?

 

[LostKiwi]

If it locks off the internal switch the PSE pump is probably ok.
You need to get it on Star to see what it reports and test the system.

 

[MW]

Tried an OBD 2 test today (connector is behind the bonnet release handle). Showed nothing. I suspect this is not sensitive enough. Car still locking as normal on the interior switch. Even the petrol flap locks as normal. Any good Mercedes independents in Suffolk?

 

[MW]

Managed to get the key to work in the lock, but it will not lock it. Is this normal. i.e. the key only starts the engine and UNLOCKS the doors in an emergency if the fob keys fail? Checked the foam near the PSE pump today and everything was dry.

 

[Blobcat]

It should lock the car as well, the lock will be jammed up from lack of use. Get some lubricant in and keep working the key and it should free up.

 

[MW]

Brilliant. That is why this site is so good.
Squirt of WD40, nothing happens. Do not want to force it. 20 seconds later, it locks and unlocks perfectly. The lesson here is for all 'central locking users' to use the key and a WD40 squirt, twice a year

 

[Blobcat]

Brilliant. That is why this site is so good.
Squirt of WD40, nothing happens. Do not want to force it. 20 seconds later, it locks and unlocks perfectly. The lesson here is for all 'central locking users' to use the key and a WD40 squirt, twice a year

Ok to use WD40 to clean it but get some silicone lubricant into it. WD40 isn’t a lubricant

 

[McDonald]

Brilliant. That is why this site is so good.
Squirt of WD40, nothing happens. Do not want to force it. 20 seconds later, it locks and unlocks perfectly. The lesson here is for all 'central locking users' to use the key and a WD40 squirt, twice a year

That's a nice, inexpensive outcome. Well done the forum.

 

[MW]

UPDATE
Took the car to an independent Mercedes Benz garage. They diagnosed fuse 3 had blown. When replaced the alarm siren was playing up . Apparently this is a common fault. The unit had blown the fuse. It also is connected to the central locking. £85 to replace and all is well. Thay also cleaned out a number of front, and the petrol filler water drain pipes. In the front these can cause electrical problems. Labour was 55 minutes, yes he charged 55 minutes! How fair is that.
Absolutely first class service. He uses MB parts and labour is £65 an hour. A real find, and Alex is ready to talk and listen to car problems. He diagnoses, and fixes rather than replaces. Got him off the web, and no connection. He is Alex Crow at: http://alexcrowltd.co.uk/
in Stowmarket, Suffolk.

 

[LostKiwi]

UPDATE
Took the car to an independent Mercedes Benz garage. They diagnosed fuse 3 had blown. When replaced the alarm siren was playing up . Apparently this is a common fault. The unit had blown the fuse. It also is connected to the central locking. £85 to replace and all is well. Thay also cleaned out a number of front, and the petrol filler water drain pipes. In the front these can cause electrical problems. Labour was 55 minutes, yes he charged 55 minutes! How fair is that.
Absolutely first class service. He uses MB parts and labour is £65 an hour. A real find, and Alex is ready to talk and listen to car problems. He diagnoses, and fixes rather than replaces. Got him off the web, and no connection. He is Alex Crow at: http://alexcrowltd.co.uk/
in Stowmarket, Suffolk.

And is a member on here

 

[Blobcat]

UPDATE
Took the car to an independent Mercedes Benz garage. They diagnosed fuse 3 had blown. When replaced the alarm siren was playing up . Apparently this is a common fault. The unit had blown the fuse. It also is connected to the central locking. £85 to replace and all is well. Thay also cleaned out a number of front, and the petrol filler water drain pipes. In the front these can cause electrical problems. Labour was 55 minutes, yes he charged 55 minutes! How fair is that.
Absolutely first class service. He uses MB parts and labour is £65 an hour. A real find, and Alex is ready to talk and listen to car problems. He diagnoses, and fixes rather than replaces. Got him off the web, and no connection. He is Alex Crow at: http://alexcrowltd.co.uk/
in Stowmarket, Suffolk.

Is that a paid for "Advertorial"