Contact Warn and I'm sure they will send you a new one. It looks like the same remote that comes with the cheaper winches (Viper). If your not needing the remote (or want both) I would install a flush mount switch in the dash somewhere that is handy yet out of the way. I'm guessing you would want it on the left side of the steering wheel so you could shift while lifting the plow?
I was disappointed that I had the exact same thing happen to my controller. It still works just the covering cracked in the extreme cold weather. I do prefer the remote control vs the fixed switch I had on my old machine. I plan to upgrade with the wireless version next.