I just bought a 2000 slk 230, and it has the factory keyless entry/alarm. When I arm it the little red light for towing flashes but there is no sound, it just flashes the blinkers 3 times and locks the doors. I've tried arming and opening the door without unlocking it first and nothing happens. I've even armed it while I was inside and started the car and nothing happens. Anyone had this problem? is there somthing you have to do for the alarm to start working?

 

Check system works as follows.

Lock car with drivers window OPEN.
Wait 5 secs for system to ARM. Red flashing light in Radio and Tow switch.
Reach in and OPEN door using inside handle.
Alarm should sound.

A further check is to jack the car up with the system ARMED. The alarm should go off.

I suspect that there is nothing wrong with your system. It is not intended to "Bleep" at you when you arm it. Only the external lights (different dependent upon territory) feedback and the flashing red lights.

IUf it is NOT working then you likely need a new PSE unit. See other posts on this subject as recent as this week.

Keep us posted.

Stuart

 

I armed it the other day and went back and opened the car like you said from the inside with the window down and nothing happend. I havent tried jacking it up but if it wont go off when somebody breaks my window and opens the door I think its not working right. I tried hitting the roof the hood, the doors, the trunk with my hand and it didnt do a thing.
What exactly is the PSE and how much does it cost? would it be cheaper to get a aftermarket alarm?

 

OK, so it appears that the system is NOT working correctly as you originally stated.

The PSE is a "blackbox" located beneath the flloor of the boot on the RHS in a foam box (next to the jack).
It controls Security, door locks, interior light and bulb warning. It is a strange mix of electronics, electricals (relays etc) and mechanical components (pump/valves).
Lots of people have trouble with one or other of the systems listed above.
Usual scenario is that a little wqter/dampness has got into the unit due to water from the roof dripping onto the wires when the roof is stowed wet/damp.
Search PSE and you will find lots of posts.
Easy to replace.
Cost 200/300USD range.

However, could just be be siren located in plenum chamber immediately in front of the windshield.
Best approach is to get the diagnostic codes read by a DEALER or a garage with equipment which can read MB body codes.. This indicates the type of fault. CAN'T use low cost scanners which most garages have to read engine diagnostics.

A aftermarket alarm system will replace security function but unless you isolate the integrated systems....not sure how you would do this.....you may find that the existing fault results in one of the other integrated systems going wrong next. Worst scenario is the IMMOBILISER kicks in.

Are your other systems OK especially the interio light. Works when the doors Open/Close?
Stuart

 

Now that you mention it my interior lights dont come on when the doors open when I put it in the middle the lights just always come on. And when I switch it to the right they also always come on..... I almost forgot about the problem, seems the door sensor could be a problem?

 

100% confident.
Faulty PSE.
Stuart

 

Can the PSE be fixed or to you have to spend $300 on a new one? I could get a nice alarm installed for $300

 

If you know your way around fairly well with a soldering iron, you could fix this yourself for far less than $300...I'd say more like the cost of solder and your time.

 

Unless you are an electronics wizard I think you are looking at a new PSE.

Repairing the pump and relays inside the box is quite feasible but the problem with the electronics side is the small size of the components, not knowing what the circuitry and correct value of resistors etc. Even once that is sorted incorrect voltages across the pins of the processor will most likely have destroyed the circuitry.
Once the corrosion was removed (it was extremely slight) I still couldn't get the unit to perform CORRECTLY.

If you PM me I will send photos of the circuitry for you to decide whether you wish to try the repair route which shows the nature of the corrosion and the type of circuitry you are dealing with.

An after market alarm will not address your interior light problem, the possibility that the immobiliser will operate one day when you least want it to and other systems that are potentially waiting to go wrong. ..e.g. Door locking and bulb monitoring.

Get yourself a PSE of eBay but make sure you get the right one. Or buy from MB and fit yourself....a few minutes work.

Stuart