Do yourself a favor, remove the headlights, takes about 2 min. on each side and you can confortably work on your bench or in the living room if you want...
Otherwise, you'll end up with skinned knuckles and a sore neck. Once you swaped the modules from one lamp to the other, just put the lamps on top of the rad and plug them in. this way if you have any more work to do you won't have to remove the lamps one more time.