I have a goodman heating unit model # RUF048-008-1. When the unit kicks on it kicks back off after 3-5 seconds. Also I have a purple wire that I don't know where it goes.

Sounds like a dirty flame sensor, or the flame sensor wire is unhooked (purple wire unhooked from flame sensor probe). Can you post some pics of the inside of your furnace, all around the burner area, and the unhooked wire? I should be able to tell you wear the wire goes. The more pics the better.

Thanks mygirlsdad77. The heating unit is electric. Could you please send me anything you have do maybe I can get it going. Thanks

Oh, sorry. I don't do much work on electric units. Mostly natural gas and propane. Sorry I can't be of more assistance on this one. We just don't have many electric unit in my area, as electricity is much more expensive than gas in our neck of the woods.