I will attempt to explain all that I have encountered and still try to make sense.

I recently (about two weeks ago) went out to start my 2016 Zforce 800 EX. I had to jump start it but then it worked fine with no issues (Including the plow going up and down with no issues in the winch switch). Fast forward to two days ago, I went out to start it so I could plow my driveway and had to jump start it again. After letting it idle and warm up I hit the switch for the winch to lift the plow and it instantly died. When trying to restart all I got was a rapid clicking noise. I let the machine sit for a couple of hours before trying to start it again, it fired right up. Tried to lift the plow and it died followed by the clicking noise again when attempting to restart. At this point I noticed the switch for the plow was only working when running the cable out, the "in" quit working. I hooked up the remote switch and could run the plow in or out without issue.

Yesterday my wife went out and jump started it but it wouldn't idle on it's own, she had to keep the RPM's up or the jumper on the battery or it would die. I pulled the battery and it tested at 12.7 volts.

I have no idea what to try next. Thank you in advance for any help. I hope my post makes sense....

I suspect that battery, and I know you said it measured at 12.7 volts at rest. I would put a voltmeter across the battery when its in the vehicle and hooked up. Watch the voltage when you hit the starter and when you unhook the jumper, and when you hit the winch. Look for how much the voltage drops. That clicking is low voltage.  A 2016 has had lots of time to deteriorate depending on how old the battery is and how it was activated for service.

OK, will do. Thank you!

[2015 Z Force 800 53/Trail EPS]

Battery acts like it's not been on a maintainer between uses and has been used without a full charge. That and it's age may be a factor. These wide swings in voltage also can..(not saying it has..yet..) cause problems in the ECM as in burn-out. Even though it may show 12.7 volts have it load tested and if it is over 3-years old now, replace it and always keep it on a maintainer between uses. My fingers are crossed for your ECM. Tuck this in the back of your mind: The winch will pull 20 amps to rotate. For every 5 seconds of that draw, it will take up to 20 minutes of the engine running above 2200+ rpm to put that energy back into the battery. Now compound that with all the raisings and lowerings one does plowing snow. You can easily pull all the life out of a battery and take hours, maybe a day or more to re-charge it on a tender. Just starting it with the starter takes 30 minutes+ to completely put back in what the starter took out. Yeah.. 

Thank you for the very helpful and informational response!

A new battery seems to have fixed the issue. Thank you guys for your input! Under load the old battery dropped to 10.1 volts.

[2015 Z Force 800 53/Trail EPS]

A new battery seems to have fixed the issue. Thank you guys for your input! Under load the old battery dropped to 10.1 volts.

Good. Yeah 10 volts is a bad-thing...lol.