02 grizzly 660 wont start

I went to start my 660 today and the battery was dead so i jumped it off and it stared. I drove it around and had it running for about 30-40min. turn it off for about 5min. and now it wont start back, I tried to jump it off again, but all I get is a buzzing sound coming from a small black box next to the battery it has two 30amp fuses in it and both are still good.

I've ran into this problem twice with 2 other grizzlys, It might not work in your case but just try it. It ended up being the cables that go on the battery, take them off clean them and put them back on tightly.. I don't guarantee it but it worked in both case we had problems just like you discribed. Good luck