An SL nightmare......HELP

[knockerblip]

So, I went into a Merc 'specialist' for a new starter battery in my 2004 SL350. They persuaded me to have a new convenience battery as well although I have never experienced problems with the old one. So £350 later I drive away.Next morning I cannot get into the car by remote so use the key. None of the convenience functions are working.
Back to garage who test and tell me they have installed a duff Merc battery. They change in for another one.
Next morning the same thing. An electrician pal puts his tester on and finds there is a 3amp drain.
We close the boot with the battery disconnected.
Problem 1.....We now cannot get into the boot as the boot lock does not work...any ideas please
Problem 2.....what could have happened on change of battery that could cause such a battery drain.
Of course the garage response 'it's nuffin to do with us Gov'

 

[Alps]

Doesn't sound like much of a specialist, anyhow, lets get you in.

you can use the key on the boot also to let you in, turn the key and then press the release

convenience battery is under the bonnet and there should be a positive post under there too to connect a charger. I would try not to use a booster as this can effect electrics.

once charger is on you should be able to access the boot as normal.

at this point it would be wise to get the batteries checked.

do you have full mb service history (and if it was serviced by mb last), then you can call mobilio out to sort it for you.

where in the country are you based, so we can recommend a decent specialist.

 

[flowrider]

On a 2004 SL the convenience battery is in the boot! The starter battery is under the bonnet. If you look under the boot lip where the boot release is you will see a keyhole which if not siezed will release the boot.

 

[knockerblip]

Firstly thanks for your suggestions.
Now an apology as I have not made clear the issue which is:-
....Neither the remote key will work (as the boot battery is flat) nor will the manual key work as the boot key lock is seized. As Flow, you touched on.
....The batteries, starter and convenience, are both brand new Merc issue.
....the change of the batteries has resulted in a 3amp drain when everything is switched of.

So the first problem now is how do I get in the boot short of levering it open.

And then, understanding why a change of battery can instigate a usage drain.

I do have some sympathy with the garage.....all they have done is fit two new batteries and that is not something you can really do incorrectly.

 

[Terry_]

Without any power supply you have to either free off the manual key release or break into the trunk

If the main vehicle battery is disconnected I cannot see any other way

 

[CabrioDave]

When you say "battery disconnected" - how?

This matters because: if you've taken off the terminals, but those terminals are not touching each other, and the +ve terminal is not touching any bodywork, you can find somewhere else on the car that would be fed by the convenience battery, and connect a battery there. This would feed 12V "backwards" towards the battery terminals - but more importantly, to all connection, en route, that that battery would usually feed.

Once those circuits are live, the remote key should work.

No?

 

[Terry_]

Just to add I cannot see how any garage could cause a battery drain

 

[flowrider]

Firstly thanks for your suggestions.
Now an apology as I have not made clear the issue which is:-
....Neither the remote key will work (as the boot battery is flat) nor will the manual key work as the boot key lock is seized. As Flow, you touched on.
....The batteries, starter and convenience, are both brand new Merc issue.
....the change of the batteries has resulted in a 3amp drain when everything is switched of.

So the first problem now is how do I get in the boot short of levering it open.

And then, understanding why a change of battery can instigate a usage drain.

I do have some sympathy with the garage.....all they have done is fit two new batteries and that is not something you can really do incorrectly.

The key in the lock is the only way into the boot without causing damage. Try some WD40 in the lock and leave it for a short while and try the key again.

 

[4life211]

In my w211 55 amg the same problem with lock and battery. The mechanic have destroyed the plastic where the plate is mounted in trunk.The second problem might be the BCM or the diode block of alternator , or voltage regulator. Mine has diode block replaced the alternator solved.

 

[flowrider]

Just thought of something...........i read a post somewhere that access to the boot lock can be gained by drilling a hole in a specific location behind the number plate, not ideal but maybe an option.

 

[moonloops]

Just thought of something...........i read a post somewhere that access to the boot lock can be gained by drilling a hole in a specific location behind the number plate, not ideal but maybe an option.

No, most cars you raise the boot using little airbags, locate the wiring loom to the boot lock and apply 12v to the correct central locking wire. This pops the doors and boot open. Takes about 5 to 10 mins with minimal damage.

 

[4life211]

Just thought of something...........i read a post somewhere that access to the boot lock can be gained by drilling a hole in a specific location behind the number plate, not ideal but maybe an option.

You are right.

 

[markmifsud]

When you say "battery disconnected" - how?

This matters because: if you've taken off the terminals, but those terminals are not touching each other, and the +ve terminal is not touching any bodywork, you can find somewhere else on the car that would be fed by the convenience battery, and connect a battery there. This would feed 12V "backwards" towards the battery terminals - but more importantly, to all connection, en route, that that battery would usually feed.

Once those circuits are live, the remote key should work.

No?

Best to connect a 12v light bulb in series so that the max current pulled is controlled by the bulb (just in case of any shorts in the boot). You could just fuse the connection but by using a bulb you have visible evidence that you have the connection.

 

[knockerblip]

I have seen the drill hole option....some guy has usefully given precise drilling instructions.

The boot was shut after the pse pump had been disconnected and the battery disconnected so that the battery drain could be investigated with a meter. The reasonable assumption was that the boot could be opened with the key.


It really is not a **** up at the garage but a **** up at manufacture that leaves the lock vulnerable to seizure....after all the boot key lock might not ever have been used and the car is 13 years old.
As there is a fuel tank in the way access via back seat does not look an option.

Anyone have any thoughts on the initial problem of why a battery drain should suddenly occur following a simple battery change. That is the biggest mystery

 

[renault12ts]

Does the metal key open the drivers door?

And if it does, can you not open the bonnet and connect a 12v supply to the post under the bonnet?

It has been suggested already.

Plenty of WD40 and patience will see the boot lock work. We've all been there.

 

[flowrider]

What about getting a locksmith to get the boot lock working.

 

[c63chris]

As above if you get the car started the electronics will use the starter battery to power the convenience circuits until the convenience battery is at a set voltage i.e. charged. When the starter battery is in use like this you should be able to open the bonnet.


Sent from my iPad using Tapatalk

 

[Darnott]

knockerblip,
If the rear battery is connected, I can advise how to open the roof and therefore gain access to the boot, this is possible even with the PSE locking pump disconnected.
If the rear battery is disconnected then to get into the boot you will need to either break the central brake light or drill a hole after removing the number plate.
After you get the boot open we can advise further.

 

[knockerblip]

Renault.........yes, the key works on the doors but not on the boot lid. The pse pump is disconnected so there is no way of using the electronic system. And yes, I've heard that constant WD following by gentle turning will eventually work but it hasn't yet.

 

[jaymanek]

Why did you change the battery?

There is no way the change of battery has caused your drain.

It was either there before prompting you to change the battery or its happened coincidentally.

the drain has to be narrowed down circuit by circuit. Its normally a control module somewhere not shutting down...
Could be the PSE pump, or possibly a seat controller... or any number of components.