Mechanical help

This is going to sound very strange but it is a strange problem that my 4x4 has developed. I know it sounds completely crazy and it is if you ask me. What does the transmission have to do with my heater fan blower. Here's the problem every time I put my 93 ford explorer into reverse it blows a fuse to the blower to my heater. If there are any mechanics out there that can help please leave comment I would greatly appreciate it thank you. My explorer is the last thing I have running my faithful escort pony has decided to die she will only do about 5 miles per hour and I am told that fuel is getting in the oil. For being a 225.00 dollar car she gave me 6 years of very dependable service and I hate to see her go. My pony has been the longest lasting car I have owned I was going to pass her on to my oldest because she was so reliable. She is nothing special to look at a car wash would probably make the whole body fall off so to speak she is quite the rust bucket. But anyway if anyone has an idea of what is causing this problem with my explorer please leave comment. Being in the Midwest with no heat in your vehicle is no fun way too cold. Thanks bye all.