Ha - just read your post about hooking up the battery wrong, and I did the same thing on my wife's New Holland TZ25da - as the battery lost power and needed to be changed.....well, it turns out that after changing the battery that the alternator was not charging, so after having problems finding the exact replacement alternator - I replaced the internal regulator on the alternator and all good now... So, the first problem was the 40A slow blow fuse and after locating it hidden in some wiring harness under the engine I found the special fuse at Advanced Auto Parts - cost around $8, and it worked to get the tractor running. I picked up a spare on eBay for a few bucks too....