SL350 central locking problem

[spokido]

Hi Malcolm
I Pulled the PCE out but have not had time to check , went back to the car to day 29th July opened the door hear noises from boot and now the central locking is working and the 20 amp fuse hasn't blown.

This is weird , will check the electrical connections and take photos how do you release the grey blocks is it just pull or a clip some were

thanks
wade

 

[television]

Ease back the tabs in the slots, and they lift off.

 

[David Arnott]

The fuse for the PSE/ central locking pump is f71, it should be a 20 amp. yellow fuse, on your car someone has fitted a clear 25 Amp. fuse, see photo.
This is not a big problem , some of the PSE unit take more current than others so 25 Amp is OK if needed but do not be tempted to fit a larger fuse because the the wiring can melt etc.
The PSE is working now because you have reset it by disconnecting and reconecting the power, if you are lucky, all will be fine.
If you are not lucky the the PSE will shut down the functions that have a leak.
Or there maybe a problem with corrosion caused by the all too common problem of water in the boot.

 

[television]

I have told a few member to use a 25 amp fuse. I have had 2 here for repair where they were fine but pulled 19 amps under no load.

 

[spokido]

The fuse for the PSE/ central locking pump is f71, it should be a 20 amp. yellow fuse, on your car someone has fitted a clear 25 Amp. fuse, see photo.
This is not a big problem , some of the PSE unit take more current than others so 25 Amp is OK if needed but do not be tempted to fit a larger fuse because the the wiring can melt etc.
The PSE is working now because you have reset it by disconnecting and reconecting the power, if you are lucky, all will be fine.
If you are not lucky the the PSE will shut down the functions that have a leak.
Or there maybe a problem with corrosion caused by the all too common problem of water in the boot.

David
The issue is I didnt disconnect any think I just looked at the unit to see how to disconnect but gave up as previous appointment ,and replaced it back in the tray no water etc.

This seems to be an intermittent faulty I've not even changed or touched the fuse this was done by the garage why would different components just stop working then when I went back to the car to day it all works except for the remote boot unlock as per my first post

wade

 

[David Arnott]

So to be clear everything works at the moment?

doors lock / unlock ?
boot lid open (from handle on lid) ? boot soft close (pull down)?
roof will open (as long as luggage separator is closed) ?
petrol flap lock / unlock
interior compartment (glovebox etc.)
boot open from switch on drivers door ?

But the boot does not open with the button on the key, Yes?
That is the only fault now?

 

[spokido]

So to be clear everything works at the moment?

doors lock / unlock ?
boot lid open (from handle on lid) ? boot soft close (pull down)?
roof will open (as long as luggage separator is closed) ?
petrol flap lock / unlock
interior compartment (glovebox etc.)
boot open from switch on drivers door ?

But the boot does not open with the button on the key, Yes?
That is the only fault now?

Hi David
Ill reply in the order as above
1.doors unlock and lock by key fob.
2.Bootlid need key to open Boot soft close don't know what this is see my photo.
3.Roof opens and closes when separator is closed.
4.Petrol flap locks and unlocks off key fob.
5.???
6.Boot does not open from switch on door or from key fob.
7.Boot does not open from key fob.

Also the Mercedes Workshop and repair manual states that F54 is the fuse for my car which is 20 amps and the F71 does something else , my car is a SL350 2005.

I cleaned the micro switch for the separator as advised by Malcolm which seems to have fixed some issues, is that Because their all tied in to the CAN which I don't know what that means.

I get the impression this is something to do with the CL Trunk opening valve would that be a fair comment.

Thanks for your time
wade

 

[television]

The soft close is where when you close the boot lid, the PSE pump pulls it down tight.

You problem is with the rear lock itself 10, or the vacuum to the lock around 70

 

[television]

I have never looked at the boot locks, could it be electric and a broken wire in the hinge area, as only the one vacuum pipe that must be the soft close.

 

[David Arnott]

OK, now we are getting somewhere.

The fuse IS f71, the one I circled in red on your photo, 100% sure.

To proceed, do the following, you need to disconnect and reconnect the power to the PSE.
so either

1. pull out that f71 fuse (clear 25 Amp on your car) and then reinsert.
OR
2. pull off the larger (10 pin) plug on the PSE then plug it back in.

Do either of the above and then see if the boot lid will open and close correctly. This might function for a few times then fail again, but do the above and tell us what happens.

 

[television]

Ok just read it all and the PSE pump is used for the boot opening. This providing that the metal key has not been turned to the 90º position.

 

[spokido]

Hi David
Ive checked the boot I have soft close when the roof is up and when the roof is down, so Im thinking as Malcolm advise lock issue the only other issue is the driver seat doesn't inflate and I understand this is on the same system tested it yesterday .

 

[spokido]

The soft close is where when you close the boot lid, the PSE pump pulls it down tight.

You problem is with the rear lock itself 10, or the vacuum to the lock around 70

oK checked the boot it soft locks on roof up and roof down
agreed with your comments will investigate further is there a supplier people use who are cheaper than Mercedes dealers thats the main question

 

[spokido]

OK, now we are getting somewhere.

The fuse IS f71, the one I circled in red on your photo, 100% sure.

To proceed, do the following, you need to disconnect and reconnect the power to the PSE.
so either

1. pull out that f71 fuse (clear 25 Amp on your car) and then reinsert.
OR
2. pull off the larger (10 pin) plug on the PSE then plug it back in.

Do either of the above and then see if the boot lid will open and close correctly. This might function for a few times then fail again, but do the above and tell us what happens.

OK Ill do that today thanks David

 

[television]

oK checked the boot it soft locks on roof up and roof down
agreed with your comments will investigate further is there a supplier people use who are cheaper than Mercedes dealers thats the main question

That shows that the vacuum is at the boot.


I think broken wire.

 

[David Arnott]

spokido

Here is how to do more fault-finding.

Problem 1. The boot release handle micro switch or associated wiring will be at fault or if unlucky the connector on the PSE.
Please see the attached three pages of pdf files that I have made for you.

The main wire is the brown with yellow tracer from boot lid switch (via connector X8/4) to PSE pump (conn.2 pin1)(small 6 pin connector).

PSE pump = A37
Wiring connector in boot = X8/4 (conn. 1)
Microswitch in release handle = S88/8

So you need to put a multimeter on pin 1 and check that it goes from 12Vdc to about zero when the boot lid release handle is operated

Please try this and come back with your observations.


... some more info, to help you.

When you operate the handle in the boot lid this makes the PSE pump blow pressure to the lock mechanism, the pneumatic solenoid then directs this pressure to the black diaphragm part which unlocks the boot.
The white diaphragm part is supplied from the PSE with vacuum when you close the boot lid on to the first click of the lock, the boot lid then is pulled down and locked with a further click.

The pressure and vacuum are applied on the same yellow plastic line and is then directed to the appropriate diaphragm by the solenoid. The PSE can make both pressure and vacuum.

 

[spokido]

Opened the car from the key fob drove to town 30 minutes away ,got out the car pressed the key fob to lock the car "Nothing" Pulled the fuse then placed back in "Nothing" locked the car manually with the key went shopping came back Tried to open car by key fob "Nothing"
Drove home parked car tried to lock car from key fob nothing ,no roof,no petrol cap "Nothing".

The only thing I have touch in the car was the seat lumbar switch which doesn't seem to pump up any support.

I tried this yesterday and the passenger side pumps up and vents when using dial on seat the Driver however doesn't could this be the air leak I wonder .

So Im back to were we stared gents Ideas

WADE

 

[David Arnott]

OK,
Now we have too many inconsistent, intermittent problems.
The best (only?) way forward is to get a good auto electrician on to the car , they MUST have an STAR diagnostic system to see the faults and values.
A good electrician will find the problem(s) within 1 hour.
I am a humble oilfield engineer and I could find all the problems in 15 mins.
This is not rocket science.

To help you even more, I can send you a 100% tested and working PSE unit which you could fit and that substitution will rule out if you have a faulty PSE.
If it makes no difference you just have to send back the PSE and just pay the postage (£15)

 

[television]

The seat function runs on its own, and should not affect the rest of the car locking at all, any leaks and this function is turned off, the rest of the car should still work re the locking.

If you pull F71 again for 10 mins and replace, it could all come back to life.

If the system has no leaks, the pump should run and cut off within about 4 seconds, if it runs up to 17 seconds, then a leak shutting it all down. You can hear the pump with the boot closed.

 

[spokido]

OK,
Now we have too many inconsistent, intermittent problems.
The best (only?) way forward is to get a good auto electrician on to the car , they MUST have an STAR diagnostic system to see the faults and values.
A good electrician will find the problem(s) within 1 hour.
I am a humble oilfield engineer and I could find all the problems in 15 mins.
This is not rocket science.

To help you even more, I can send you a 100% tested and working PSE unit which you could fit and that substitution will rule out if you have a faulty PSE.
If it makes no difference you just have to send back the PSE and just pay the postage (£15)

Thanks David I work in oil and gas lol did the multimeter and it was zero soon as I did the test with out even touching the boot lid release

Cheers
Wade