Park your car at N51 56.033 E9 56.944.
Go the way from N51 56.032 E9 56.882 to N51 56.414 E9 56.887. At
this point, leave the way in direction 325 degrees and go straight
uphill, towards N51 56.576 E9 56.707. That's the starting
point of your cache hunting.
There you can look around the ruine of the tower. The cache
itself is within a radius of 100 m around the starting point.
It's a thing build in 1989. The sign on the thing shows some
symbols, one is a tool.
Send me an email with a description of the thing and the name of
the tool to verify you have found the cache. Don't post your answer
here, even if encrypted.