Remove the ham from the refrigerator and let it sit at room temperature for 1-2 hours prior to cooking.
In a bowl: place brown sugar, pineapple juice, maple syrup, dijon mustard and mix well. Set aside.
Coat the slow cooker with cooking spray.
Remove the ham from the package.
Place the ham (face flat side down). Pour the sauce mixture on top of the ham.
Cook on low for 8 hours or high for 4 hours.
Remove the ham and place a cuttting board or plate. Cover with aluminum foil for 15-20 minutes before serving. Reserve the sauce mixture.
Switch the cook temperature to high. Cook for 15-20 minutes or until it thickens to your preference. Alternate method; transfer the sauce to a pan and cook on the stovetop on medium high for 8-10 minutes until it thickens.
When ready to serve, slice the ham and transfer to a serving platter. Pour the sauce/glaze over the ham.