2005 Hyundai Terracan car problems

Hi there, I have a problem with my car please help I was driving for half hour before hand, went home put a trailer on to drop around the corner and all of a sudden I lost power from 2nd and 3rd gear it started to smoke from my drivers wheel so I stopped the car, this happened 1 week ago but now I have noticed more problems my hayman light comes on when im breaking that has not done that before and my car feels very heavy and sluggish to drive the temp is fine my gears are fine now to drive, I did take it to a mechanic and he connected some electrical devise under my dash that picked up a faulty fuse in my acceleration he pushed a button on it and checked it again and said no error found. I was to;d I have slipping gears thats why it smokes but im thinking its my breaks that have locked up does anyone think it may be my breaks too locking. Please help need advise. Thanks mish.