Hi Pizzaguy,
I really appreciate the help you give, but I don't remember how the lights behaved when the alarm worked. The few times the alarm was triggered before, I turned it off as soon as I could because of the noise. I didn't study in detail what happened on those occasions.

What works today is the switch on the dashboard to lock or unlock the doors. The pump starts in the CLP/SSM unit so it works. But of course, the alarm doesn't activate and it shouldn't.

If I lock with the FOB, the alarm (siren) starts immediately, nothing else happens, nothing locks. And I wrote wrong earlier, the green turn signal lights on the dashboard don't flash either. They did before when the alarm worked.

The siren that is installed today only has 2 cables in, +/-. No separate power input. The original has 3 cables in, two of which are for power, the third is the signal input from the CLP/SSM. I don't think the CLP/SSMM unit can deliver the current needed and that they put a relay in between to make it work, but I don't know how much current the CLP/SSM can deliver. Some amperes into the siren and it sounds loud. But this isn't a problem, it has worked earlier.

It's common for them to reroute the cables for the turn signals and rewire them and maybe some other wires here in Sweden. Some stupid rules that have to be met that cause problems and cost a lot of money. I hope to figure out what they did to the car's electrical system later, I can see traces of what they did in some places.

I've taken the CLP/SSM unit apart and can't see any water ingress or corrosion damage. If I'm unlucky and it's defective, you wrote that it doesn't need to be programmed. What do you think, can I replace it with a CLP/SSM from any Mercedes from the years 1997 to 2004? My unit has a Mercedes logo on it.

I think we can wait a while now until I examine the tailgate switch, or if it is the cable to it that has become pinched.

Very good information you gave: "The anti-theft/alarm system is integrated in what they refer to as the 'Power locks', so no.", thank you very much, I have been looking for that information!

Thank you very much for your help, I will be back!

Lars