SLK 320 electrical short starting problem

My 2001 slk320 has been having starting problems. There is possibly an
internal short somewhere that occurs when trying to start. I have disengaged
the alternator harnesses to eliminate one source of the problem. It almost
started then after trying again it would not, and then a very strange and quite
audible warning sound (not the antitheft alarm) came from under the
passenger side dash that ran for about 1 minute and stopped. Like
dadodadoda.... at a rate of 3 per second.  
I have been testing the car with a volt meter and taking current readings by
putting a charger across the battery. I think the alternator is OK, but I pulled
the power and control line off of it. Maybe that was a bad thing to do. But I
think the car should start without it and it almost did. The diode on the
alternator tested OK. Have not tested the starter. I took reading of the three
electrical leads stemming from the main 12V line. They are F2-Electronic
suction type fan, F3-Hydrolic Unit (traction), F4 Fuse box, terminal 30.
Yesterday I was trying to chase down what appeared to be a short at F4, it
went away. All 3 lines show some capacitance, and I would expect that to be
normal. OK ready for the expert. How much will it cost?