Ok I found this on another site.
The post May-1998 SLKs don't have the K56 relay - replaced by the link in your picture according to the WIS.
Also that picture that just showed up in your earlier post cant have an ignition relay since the power is common on that bar from the battery so its powered all the time. So if you have power at that bus bar and the back of the alternator you dont have a connection issue.