Thats a common dilema here in soggy southeastern MA,especially THIS year,with noting but rain rain rain!..I am forever having to clean corroded connections on wiring on everything I own that has a battery or wires,and everything else too!..things sit more than a week or two here and it corrodes on ya..
I dont know if shrink wrap will help though,maybe if you spray some white lube or put grease on the connections first it might help prevent corrosion,otherwise it may trap condensation and make it worse!..I find leaving things oily and greasy the best method to preven rust and corrosion here,I wish I had sprayed drian oil on my truck as soon as I got it and did it twice a year since,it wouldn't have rotted away like it has if I did..
