Electrical Short

I have a 1990 5.0 auto Mustang convertable with a short in the blue wire from the starter solanoid to something. I think to the eec unit. I put a DVOM between the neg terminal and te ground and have over 250 mamps draw. It will run a new battery down overnight. Can anyone help. I need to know where this wire goes and is it suppose to be hot. It may be the eec unit is bad but when the new battery is charged and full the car will start and seems to run fine. It just happened overnight with no notice.
I need some help.
Thanks,