Hi ,
I have a 2000 slk 230 , when i'm driving sometimes the door unlock also the interior light comes on & off driving & stationary. in addition to that the alarm goes off .

This is driving me crazy as when I take it for diagnostics nothings really showing up , the mechanic has come across this before & reckons its's the PSE but i read earlier it may be the key .

Any ideas guys ? also the PSE is around £1000 if it is that does anyone know a cheaper non manuafcturer part ?

Thanks

 

Likely it is the PSE but you need to give a fuller description of the exact symptoms before I will confirm this to the best of my ability.

For instance does your interior light stay on permanently when you select doors on the interior light above the screen?

You say your dealer states nothing shows up. What does this mean. An MB main dealer? Did they use Star Diagnostics? If so you infer no codes were present?

PSE's don't cost £1000 more like £300 but that is a guess.

Part is made by Hella but is only available from MB.

I believe that a company may repair these units (similar to the instrument cluster problems) but I wouldn't recommend this route. Almost as expensive.

Its a 10 minute jon to fit it yourself. No special tools.

Can get second hand PSE's off eBay. Just make sure you get the correct part number...or at least the same series with an updated version number.

Usual problem is water ingress (only a tiny spot) into the PSE via the wiring socket from stowing a damp or wet roof.

The security system, bulb monitoring, door locking, interior light plus rear lighting are all controlled by this unit using digital control techniques.

Stuart

 

Hey buddy, check both door switches replace problem switch and your done .............. To be a little more in depth while your driving the body and doors "flex" a problemed switch will often will act up then. And that will illuminate your interior light and lock actuator. AND as far as the alarm goes think about it.... When the car sees the door is locked and that switch acts up the computer see a signal showing that the door is being opened Ex. Broken into and will inturn activate the alarm. So theirs your problem very common among that vehicle. Hope this helps.

 

Unfortunately the door switches are not wired in the conventional way.
The signal from the door switches is "interpreted" by the PSE and then a "digital" signal is sent down the CAN (digital highway) to the main power control unit in the engine bay which in turn activates other systems like the interior light and alarm systems.

A switch COULD be faulty (more likely incorrectly adjusted) but IMHO I do not believe that this is the cause of the problem. Worth checking anyway.

Stuart.