Air conditioning and blower failure

Hello guys, I have to contact you today with a problem of air conditioning. A few days ago my Omega B air conditioning system failed. After a short assessment of the problem I found out that a fuse flew. It is a 30A fuse to terminal 15. Furthermore, the blower and the heatable rear window do not work. After changing the fuse, however, the new 30s also flew again. The OFH suspects a short circuit somewhere to terminal. e 15 and could not help me further except that I should get an appointment to troubleshoot. Does any of you have an idea where I could start searching? For info and tips I would be very grateful.