First, combine the pineapple juice, maple syrup and brown sugar. For ease, start with the brown sugar and maple, then add in the pineapple juice.
Remove the ham from the packaging and pat it dry. The place it cut side down in the crockpot.
Now, take the mixture from step 1 and pour it all around the ham. Put the lid on the crockpot and place on low for 4 hours or until the ham is heated all the way through.
Lastly, carefully remove the same from the crockpot and serve with all the juices that had collected at the bottom of the crockpot.