Answer
All thing are possible, some are easier than others. if there is not a neg/pos switch on the radio i would rate this at a difficulty level of 6 on a scale of 1-10. (10 is f*****g impossible)you would need to open the radio up and make sure that e bit of the electronics was isolated from the casing and then change the feed wires over. also some of the components might have to be removed and replaced reversed. really much easier to get a new unit
