slk32amg alarm has gone haywire

[leighandlou]

can anyone help me pleeeese?
I have a late 2001 slk32amg ( if this is relevent) and friday night the alarm went off on the drive way. its the first time its been triggered since ive had the car so panic set in and i dived out the house to find all was well and nobody in sight. none of my pir secutiy lights were on so a little confusered but relieved. so next was to de-activate the alarm but nothing happened just the car going mad. after about 5 minutes pionting and pressing both key remotes at various angles the car eventually unlocked and silenced.
i thought i best fire it up just to make sure the immobiliser wasnt still active and all was well until i noticed that the red LED on the tow-away/motion sensor switch was still illuminated. well i turned off the engine and got out and tried to lock the car with no responce from the locking but the alarm was trying to activate as indicated by the flashing indicators.
first thought was that both remotes were running low on batteries so did the test as by the book and all was well.
next i got back in and tried the door lock switch on the centre consol to see if that worked with ignition on and off but nothing.
it was about 10pm by now so boxed car in with my 4x4 and called it a day.
next morning still the same so took it out for a spin to find it drove fine but the inicators where doing theyre own thing and staying on and illuminated( not flashing) well a few attempts att signalling left and right and they eventually went out. so decided to park up and try and get advice.
car still wouldnt lock or alarm activate ( but does flash indicators as if it was trying to).
anyway went to car today and noticed that the red LED had gone out-horrah i cried only to realise that the car battery was flat.
if im right i would say that a little LED shouldnt drain the battery.
i have spoken to MB and they said just bring it in and they will have a look. at £100 per hour plus vat i was hoping maybe someone out there could either help or point me in the direction of a good MB specialist in the east mids area.
thanks for reading and i hope someone can help

 

[coolpot]

Moisture penetrates into the PSE pump
(Pneumatic system equipment)causing the plug to
corrode, the central locking system to
malfunction, and the antitheft alarm to malfuction


Remedy

D/c Battery before mucking around with electrics
1. Locate leaks in the boot

2. Seal the leaks

3. Rotate the PSE pump 180degrees - by doing this the
lines lengthen and form a loop and water that could
run
down the lines will drip off at the lowest point of
the loop.
Info: As of September 2002, the PSE pumps are being
installed already rotated to 180degrees in the series
production.


The PSE pump is located on the right hand side of the
boot behind the lining, you will need to remove the
boot lining, on the RHS
you should then see it, it appears to have 3-4 wires
and is a long rectangular box shape!

id try taking a look at the plug(s) see if you think
water has got in, maybe give it a spray with
electrical
contact cleaner or something, if you find water is in
there then you cant really do any harm, worst is that
you
have to goto merc and have a new one..?

 

[leighandlou]

re- alarm

many thanks for your reply
I'll have a look tommorrow night and let you know how i get on.

landl

 

[BlackC55]

Another thought. The multifunction relay can also play up. Does th eroof work ok?

 

[leighandlou]

yep the roof works fine. im going out in half hour to have a play

 

[coolpot]

as far as i know with what i posted, the roof will still work ok.

let us know what you find..

 

[leighandlou]

well found the locking pump, disconnected it and turned upside down to empty out a cup full of water.
opened up the bottom cover and cleaned up the circuit board with a elecrtical solvent cleaner and a soft brush.
refitted and cleaned all plugs.
still no locking but alarm operates flashers on actvation and deactivation.
the good news is that the indicators work properly again.
the red Led indicator is still on.
can i test the locking pump out of the car?

 

[coolpot]

hmm, check the fuse for c/locking, i imagine with that water its quite a possible outcome of a blown fuse, i am not at the computer i need for info as to what fuse is what but take a look ill reply later when i get home, let me know if you sort it...defiantly worth a look....

erm, i woudlnt know about testing the pummp out of the car??? duno!

also seem as battery was flat, and d/c, its possible you need to recode the key to your car, have you tried locking the car with the switch inside??

 

[coolpot]

hmm i hope that you can figure out the fuse location hopefully they are labeled in ur car or handbook! id imagine you have aa front and rear fusebox...perhaps someone can confirm? hehe i struggle to read circuit diagram, another case where we miss malcolms greatness

 

[leighandlou]

checked fuse and all is ok. the cenre consol door switch still doesny work but that Led is still teasing me shining all happy and smug.

 

[coolpot]

2bh i suspect somethings broke with that pse.. unless someone else has other ideas? what sort of condition is it in? id imagine if there was a cupfull of water in it the board cant be too great?

i have never took one apart, dont know how easy it is to do..if its a big pain you might just want to take it in, but id imagine merc will just replace the unit..

if i were you id take it apart again, no harm, check everything out, theres a good chance the water/electric combination has eaten away some of the tracks or something.. out of interest i dont suppose the pump has a fuse on it or fuse wire...

 

[leighandlou]

it was very easy to take apart using a very slamm flat screwdriver and a little care.

i think ill bring it into work tommorrow stripped down to see if out lecky type chaps can see anything wrong with it. ill also see if that pesky led goes out when its unplugged.

I will not be beaten

ill let :-D u know

 

[coolpot]

good luck

 

[television]

checked fuse and all is ok. the cenre consol door switch still doesny work but that Led is still teasing me shining all happy and smug.

You should have really dried the PCB with a warm air gun to chase the water from under the ICs

The built in SAM where everything meets is the reason for the interaction

 

[coolpot]

TELLLLEEVISSIOONNNN TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!! TELEVISION!!TELEVISION!!TELEVISION!!TELEVISION!!TELEVISION!!TELEVISION!!TELEVISION!!


w00t!

I didnt think your be back *MANHUG!*

 

[leighandlou]

sorry to be a ickle thick but whats a SAM and what are ICs?
im an aircraft mech inspector by trade and electrical stuff is all wierd to me.

if you cant see it move it must be magic.

 

[leighandlou]

anyway had another play today and disconnected 1 plug at a time. on disconnecting the black multi plug that onnoying red LED went out so i think im on a winner. ive took it apart again and have given it another clean and am going to leave it over night to dry out thoroughly.
till tomorrow

 

[coolpot]

good luck with that, like malc says using some form of heat gun, would be good im sure, i work with computers, and ive had laptops that have water damage but after drying out switch on fine

 

[television]

sorry to be a ickle thick but whats a SAM and what are ICs?
im an aircraft mech inspector by trade and electrical stuff is all wierd to me.

if you cant see it move it must be magic.

A SAM is known as a signal acquisition module what this means is that this is a circuit that takes in information from many circuits, in this case the locking,alarm and lights, this is all info that the roof module needs, water just shorts them all together. as said this can be dried out and often OK.

An IC is a integrated circuit,as above, they are the black square things with anything up to 500 pins on them, water does get trapped underneath.

Good luck with it you should be OK

When a car goes into a MB garage, they have to replace the PSE pump to avoid comeback and give a guarantee, they have no feeling for the £800 that it cost you.