I recognize the fact that you have added threads that could help solve RCM issues, but I think you have wandered off track a little. This forum is to help people directly and save them money in the process if possible
You may not have realized it but any question that may involve the RCM always ends up with an advert for your services. I realize that it may be helpful to some people but there are threads that could prevent someone sending you a perfectly good RCM. I hope you take my words as just a friendly bit of advice, no malice intended.
There are threads of yours which explain how to do all of the work you do, how to test the RCM for troublesome relays, the horny all the time mod and the other reasons for the symptoms. Using these threads someone in trouble could have the car back on the road the same day. If you pointed out these threads of yours you could easily mention that you could do it if they were unable to.
I found the correct relay for the repair years ago and they are freely and cheaply available albeit in quantities of ten, but easily shared with members here. The resoldering of the three joints was explained in an SLK forum two or three years before you raised it here with no acknowledgement to the original SLK thread of which it is almost a copy.