W215 Flat battery, mechanical key turns but doesn't open boot

[berki]

Hi,

First let me start by saying that I have gone through a fair bit of reading before this post as seems like quite a few have had this issue, however, so far unable to get into boot.

Battery is completely flat and before it went flat there was a constant noise from the car, as if the alarm was going off but on a very low volume. It did it for a day before finally giving up.

Have tried for 4 days to get into the trunk via mechanical key, works for door and glove box, but when I turn the key counter clockwise about 20ish degrees it stops there. I believe it is suppose to stop there from what I can read but when I hold key in that position and push up on the lock around the key, not twisting and pushing on key, nothing happens. Do I need to push on the key? I can't hear any mechanics moving or nothing, the button just go straight up as when in the two other key settings.

As it seems like the alarm was quietly going off before battery died could there be some sort of safety system that would cause mechanical key to fail even after the battery is dead? Basically what I am asking is should I give up and try and find a connection point to get enough power to open boot electronically or keep going at it with mechanical key?

Have read about a few places where you could potentially add some juice to the battery like under and behind the fuse box under bonnet or under driver floor, none of which seems very easy to access. I dont believe there is any place to hook up external power on the passanger side but could there be one under the backseat behind the drive,r say under the fusebox there? Seems like that would be slightly simpler to access compared to other two.

Many thanks,

Kim

 

[television]

If the battery is flat, the key will not turn at all, that is normal.


When the battery goes flat the internal batteries in the alarm siren will quickly fail and go short circuit, so once you recharge the battery you have have to unplug the siren.

Have you tried plenty of WD40 in the boot lock ???.


The large terminal on the starter is all ways live and a battery charger joined up here would enable the remote to work. There will be a place in one of the fuse boxes, but this needs a long search.

You do need to do this as soon as possible as the battery can fail if left discharged for too long.

 

[berki]

I can turn the key 45 degrees clockwise or 20ish degrees counter clockwise. So the mechanical key does indeed turn and from what I have read the correct procedure is to turn key about 20 degrees counter clockwise until it stops and then push up. But when I push up nothing happens...

Have almost emptied an entire bottle of WD40 in the lock so far.

Btw forgot to mention that it is a 2001 w215 not sure it makes a difference.

 

[television]

I was referring to the ignition switch key,sorry about that. the boot lock key should turn I believe both ways, one way locks it so the handle has no contact, in the other direction it engages the handle and spring loaded so you hold the key and pull the handle at the same time.

I will try and check to see if there is a fuse that you could connect a charger to

 

[berki]

Thanks very much, appreciated. In the meantime will keep turning key and hope for a miracle!

I believe the internal battery in the alarm system is gone but why would I need to remove it? Will the alarm go off as soon as I connect a new battery because the alarm battery is drained?

Thanks

 

[television]

I will have a look now for a place other than the starter motor.

The siren may just go off all the time, we do not know yet.

 

[television]

Take a look in the front fuse box under the bonnet. look at fuse 40 there may not be a fuse in there, but in the fuse holder you may see connection one side only, buy touching the battery charger there may let you operate the remote, it may take a few mins for the battery voltage to rise.


Fuse 24 in the other side box may work, there will be a 10 amp fuse in there but there is a hole in the top of the fuse where you push a pin in.


Another is fuse 78 in the inside fuse box.

The best one is in the rear box under the seat and fuse 62 will do well

 

[berki]

Thanks, found fuse 40 and here is the holder. I have pulled out the holder and underneath there is a connection point, is this the one you are referring to or do I need to somehow get a pin into the fuse holder on the pic I attached?

Many thanks

 

[television]

Try in the top of the fuse with the fuse in. just push a spike or pin and hold the charger lead to it, the charger must have a good ground connection.

The dead certain one is in the box under the rear seat squab

 

[berki]

Ok there was no fuse in position 40 but there is a 40amp fuse in position 41 right next to it. Guess I can use that?

 

[television]

Ok there was no fuse in position 40 but there is a 40amp fuse in position 41 right next to it. Guess I can use that?

Look in the hole where 40 is and you will see a contact one side only, use that contact.

 

[berki]

Ah ok thanks. Thought you meant that I had to have a fuse in there and push the pin into the fuse on the side with the connection.

 

[television]

I hope that one is live as it for a heater that we do not use in the UK much, so it should be all time live.

 

[berki]

Late night update, I got in! Although using a slightly unconventional method. Basically just as I was getting ready to hook up to the fuse I noted the big red cable going in to the fuse box had a small pin hole, see attached. I checked and it had a current so against better judgement I went for it, pushed a pin into the hole and hooked up the charger.

Started off with a less powerful one and battery started charging however didn't seem to give it enough juice to control the central locking. It just gave it enough to set the alarm off. So switched to a more powerful charger and voila enough power to first lock and then unlock using the key.

Opened the door and alarm didn't go off. Then opened boot and moved and hooked up the charger directly to the battery. It is now charging but since so flat will most likely take some time.

Now all I am hoping for is that if I leave the car unlocked the alarm won't go off when I later remove the charger...

Many thanks for your help!

 

[television]

Late night update, I got in! Although using a slightly unconventional method. Basically just as I was getting ready to hook up to the fuse I noted the big red cable going in to the fuse box had a small pin hole, see attached. I checked and it had a current so against better judgement I went for it, pushed a pin into the hole and hooked up the charger.

Started off with a less powerful one and battery started charging however didn't seem to give it enough juice to control the central locking. It just gave it enough to set the alarm off. So switched to a more powerful charger and voila enough power to first lock and then unlock using the key.

Opened the door and alarm didn't go off. Then opened boot and moved and hooked up the charger directly to the battery. It is now charging but since so flat will most likely take some time.

Now all I am hoping for is that if I leave the car unlocked the alarm won't go off when I later remove the charger...

Many thanks for your help!

Pleased you are in, thats the main thing

 

[berki]

Thanks! Yeah all I hope now is that the alarm siren has not short circuited and the internal batteries will get recharged with the battery.

Otherwise I might wake the entire neighbourhood when I disconnect the charger! And doubt I'll be able to disconnect the alarm siren in the middle of the night. Guess I should read up on how to do it so I'm prepared at least.

Also realised I didn't add the pic if someone is desperate enough to do the same that I did to get in. Doubt it's the safest way though.

 

[television]

The Nicads in the siren only have a limited life, the will often go short circuit once left to discharge, they can then blow a fuse that affects the long range locking. Plus if the are dead flat the siren may not go off, this happens as the Nicads age. Dead easy to check, once the main battery id fully charged, lock the car via the remote, then unlock it with the metal key and open the door and the siren should go off. If the siren has failed they cost £90 or you can just unplug it.