I just did a little checking and found out this heating element just plugs into a plug inside the Coleman 15,000 BTU AC. Thanks for the idea.
I just found the installation for it on page 8 and 9 how to do it. If anyone wants the pdf document just email me. It looks like you just attach it in front of the AC coil and just plug in. The Thermostat controls are a little tricky but a easy MOD.