i have a guy interested in electric cooling fan on radiator on the 91 monty w/3.0 i'm parting out. i want to hook up to 12volts to test for him before i ship. plug off it has a blue and black wire . does it even matter which way i hook it up? i thought on these it spins one way and if you switch leads it would spin other way? is this correct or not. i dont want to burn it up testing it? any help appreciated - mike