I just got this cart and replaced 1 battery,after I did that one of the coils in the rear turned red hot. There are 4 posts back there with coils,I have no idea what they are! The second from the left(facing the rear) is burnt thru,what is it for? This is an older 1985 Melex 1985 and is electric,got it for the lake. I can't find a wiring diagram so am lost...HELP!!