Rear window Defogger/Demister

[Acrosstheohio]

So apparently the rear defogger switch only heats the wing mirrors if you have the power sliding window but the wiring for a rear defogger is in place should you wish to install one.
Has anyone installed an aftermarket demister such as https://www.frostfighter.com/pickup-truck-rear-window-defrosters.htm ?
My question is how do I connect into the existing wiring harness if I want to put in either a Mopar or an aftermarket product? I'd like to connect it to the existing switch which currently only heats the mirrors

 

[clifford15]

From my research the rear window defogger has it own control module or it might be integrated into a higher level module. My Tradesman does not have the wiring and I assumed no module. If you have the wiring it is a simple task to see if there is power when the mirror heat is activated. If so, go with the frost fighter kit.
If not, the task is greater because the mirror control modules are in the doors. you would need to tap off the mirror heat power to run a relay to power the window grid.