In order to convert to 12v you have to get a 12v alternator, 12v starter, and change the stator on the AC compressor. But if your vehicle is already 24v then all of your light bulbs are also 24v so you would have to change those as well. I'm putting a 12HT into my FJ60. My FJ60 is already 12v so I am just converting the 12HT engine to match my FJ60. Your relays are also 24v so you would have to change those as well. I'm not an expert at all in any of this, post and search in the diesel section for how you would go about converting a 24v vehicle to 12v. It's fairly involved from what I can see.