What Stump said. (1) pull a batt cable off (either one) (2) put the black wire eyelet on the ammeter stud along with the red wire eyelet that is already on it (both ring terminals on same stud) (3) with door shut/everything off touch the batt cable you removed back to the post & if no spark then go ahead & install it & go inside the car & see if you are good. Not sure if you have a clock or something that is on all the time but if it sparks heavy when you do (3) then do NOT reinstall the cable as there is a dead short somewhere but I believe we are dealing only with an open but I dont want to chance frying the FL. Holler back