today i turned on the heat and the heater controle started turning on and off. don't matter what setting its on. blower motor is also going off and on. relay is clicking off and on also . i changed the relay and it didn't change. where do i start looking. its a 2004 f150 lariet. thanks

 

I have a 2006 F150 Lariat with the same exact problem today. The entire heater/AC panel on the dash turns complete off (lights and all) then turns back on continuously. It repeats this, on, off, on, off, on, off. I would hate to have to take this to the shop for something simple I could do myself.