Gary, 12V DC direct short MAY have a negative effect on the tow vehicle wiring and or 'body control module' - hopefully fuses will intervene but the 'controller'* for the trailer lights on some 200+ model vehicles are VERY expensive to replace! ($200+) yikes. Take Care, Have Fun * Toyota truck 2003 uses I am told, 3 modules: Engine management, Body controls and the one that will bite you in the rear is the ABS control -no longer is it 3M splices into wiring -this will cause ABS to 'flip-out' Check with your dealership and your favorite mechanic (technician - and well earned) GO. LB/GF! M-17 # 316a 'that ain't bad gelcoat -it's "patina"! Team Geezer Racing.....Old and in the Way Arizona Sailing Squadron **************Get trade secrets for amazing burgers. Watch "Cooking with Tyler Florence" on AOL Food. (http://food.aol.com/tyler-florence?video=4&?NCID=aolfod00030000000002)