Cuts out

When the car is put in gear it cuts out, AA were called and he thought it was a fuse so replaced this, car cut out 5 times on way home with AA replacing the fuse 5 times, when we got home he had a proper look at the car and found a wire going into the gearbox that he said should not be there, so took it out, he then put the car in gear and drove it forward and back and it seemed Ok, when we went out to the car 3 hrs later it reversed out of the drive but cut out as soon as we put into 1st gear.
Car is now not being used as we need so save for repairs so any help to rectify this would be massively appreciated