Hey thanks for all the help I have converted my tractors over to 12v an a few old cars I just wasn't sure about my Mack it was at one time 24 volt it has been converted to 12 volt negative ground but who ever in the past done a bad job I have got to rewire the truck thire are cut an loose wires hanging every ware nothing works but I did get the factory radio working I thought that was amazing thanks for all the help from those who commented I am glad I joined this site it's amazing the knowledge y'all have the is a great resource for anyone who has never restored old road tractor thank alot