MY slk230 has suddenly developed alarm problems. The alarm goes off after about 15 mins . The interior light sometimes doesn' t go out and flickers on whilst driving ( with vibration) .I have checked the door switches and they appear to be ok.I cannot find the switches for the bonnet or the boot at all .Any ideas ?
All help greatly appreciated.

 

I would suggest your PSE has gone bad.

Water has got onto the PSE module/wiring below the RH side boot floor as a consequence of stowing the roof when damp/wet.

Of course you need to satisfy yourself that the door switches are all OK but the give away is the interior lamp staying on (or at least coming on intermittently, whilst in the "DOOR" position.

The PSE cannot be repaired (unless yoiu are VERY DIY) and tend to be quite expensive unless you buy them on eBay.

Ideally the modules need to be coded but you can get away without this if you choose to fit the new module yourself. (10 min job, no special tools)

If you need any more information please ask.

Stuart.

 

Ifound some moisture under the pcb in the PSE but nothing looked burnt out. I cannot find the switches for the boot or bonnet even after dismantling half of my car !!!!
I have been quoted £375 for a new PSE so i would like to check out the switches first.Do you think it is a job for the main stealer?

 

So you are in the UK? Lopcation?

£375 sounds about the going rate from a dealer.
I got a PSE for £25 off eBay and have had no problems with it whatsoever.

Very simple job to swap units so long as you have the correct unit. Must be at least the rev level for your vehicle but can be newer.

Problem with eBay is whether whoever is selling the unit can be trusted. If it doesn't work when you fit it they may not be prepared to refund your money.

If you have found water traces on the PCB the unit will have DEFINITELY had it. Your symptoms are classic.

Problem is corrosion between the CAN terminals leading to spurious signals down the CAN and causing all sorts of seemingly unrelated events to happen as a result. Alarm trigger, interior light on, false bulb warning, bouncing" door locks etc etc.

I didn't want to pay £375 for a module which shouldn't have gone wrong in the first place. I took 6 units (from an MB dealer to pieces to make one good unit but everyone had failed in EXACTLY the same way. This is a design fault at several levels.
Water from roof onto side mouldings....No warning of consequences.
Water drips of side moulding onto wiring harness. Tracks along wires to multiplug (gravity/capillary action).
Shorts adjacent CAN pins causing incorrect operation.
Enters the module through a hole in the sealing gasket. Drips onto the PCB and causes corrosion below the multiplug connection tracks which is not easily accessible without removing the sockets from the board which is difficult to say the least.
etc.etc. Got one to work again but it really is a major undertaking.
If you are interested i will send hi-res images of the workings and problem etc. send me a PM with your email. Do you have an email limit?

The boot and bonnet switches are integrated with the latches.

Stuart

 

i have sent you a pm but thanks for your help anyway.Best start looking on ebay I do believe !!
The first sign that i had a problem was the light for a lamp failure flashing intermittantly.So you appear to be 100% correct.
Thanks for info

 

Sorry location is in Derby