I found a source for wiring and auto electric goodies. I was having a hard time finding a 50 amp relay with diode built in but they have it. At a decent price and with related goodies. Check them out
http://www.wiringproducts.com/contents/en-us/d35.html
PS.. I ordered parts myself, not related too or any ties on my part, just found them doing a google search. This is the 50 amp relay with diode built in
http://www.wiringproducts.com/contents/en-us/p564.html
Jeff C