I just looked on mine and found it has the original connector still and hasn't been modified. It didn't want to come apart so I'm assuming it's burnt inside.
When I worked at Harley I installed a bunch of electrical accessories and when soldering two wires together I would twist the ends and loop the ends together then solder them. I would have heat shrink already over one end of the wire then slide it down and heat it up to seal the connection. You can use a coat hanger and solder two alligator clips to each end to make a wire holder so you can focus on the wiring not holding the wire.
The main thing is getting the material (wire) hot then adding the solder. Sometimes I use paste flux which will make it way easier to get the solder to flow onto the material. Once it flows all over the material remove the heat and let it "dry" and you should be good to go.
You really need a good soldering iron. The pistol types suck honestly. I use a Hakko adjustable heat pen style.
When I worked at Harley I installed a bunch of electrical accessories and when soldering two wires together I would twist the ends and loop the ends together then solder them. I would have heat shrink already over one end of the wire then slide it down and heat it up to seal the connection. You can use a coat hanger and solder two alligator clips to each end to make a wire holder so you can focus on the wiring not holding the wire.
The main thing is getting the material (wire) hot then adding the solder. Sometimes I use paste flux which will make it way easier to get the solder to flow onto the material. Once it flows all over the material remove the heat and let it "dry" and you should be good to go.
You really need a good soldering iron. The pistol types suck honestly. I use a Hakko adjustable heat pen style.