On my 1996 S420 the number #20 fuse keeps blowing as soon as you turn the ignition on, very sudden everytime. I definitely have a bad electrical short. The fuse chart states that this fuse pulls the (control unit and A/C compressor and the automatic climate control). I have unplugged the A/C compressor and the fuse still popped. I took the push button unit out and the fuse still popped. I am assuming the automatic climate control is the push button unit, right? What exactly is the 'control unit'? Any help would be appreciated.