@Kernol I congratulate on on your fortitude. However, considering your confusion on the problem with your car I strongly suggest you contact a repairman who specializes in Mercedes and Crossfire repaires. He will travel to your home and repair your car. Please, text:

Miami Matt's mercedes & Crossfires All of the U S A ,,,will travel .786 877 5959 text will call u back

Please, give it a try, he is well qualified, has the correct tools and in the long run will save you money and lots of time.

PS DO NOT send your car to the junk yard! There is much more to the RCM than the solder jionts. Often the contacts in the relays get dirty, or you simply have bad contact at the connectors; easily sorted out by someone with experience. Let Matt help you. He can scan your car for diagnostic codes and get your Crossfire back on the road running strong.