I know they're electric and they cycle but what are they heating? I heard they heat the intake air but would like clarification. Thanks.

 

They heat the intake air as it's drawn into the intake manifold.

Rusty

 

Theres a metal strip that has a lot of bends -[[[[[[[ so that a one foot strip can fit into a 3" hole , either end is connected to power , basicly a controled short , this gets hot so when the air gets suck in its warm .

 

Does the intake air always have to go thru the grid heater after the engine starts or is there a flap/alternate intake that bypasses the grid heater?

 

The air always passes through the grid heater. It is only energized when it is required, however.

Rusty