when should the two big fans by the engine turn on? becuase i dont think ive ever seen them on yet...

One fan runs on low and the other on high with the AC on. Turn AC off, they should stop after a minute or less.

Both fans come on at high speed at 220°F or something like that.

The AC trick is the best way to make sure that the fans are good.

Why would they come on at high speeds? when you're going fast, the air passes through the radiator quite easily. The one fan is meant to come on when the engine get to a certain temp so you don't overheat in stop and go traffic.

High speed of the FAN, not the car.

what is the override trick to get them both to go to high?

Turn on the air conditioning.

sure glad you asked this i had the same question and was wondering.

does anyone know how to test the fans?

If you want to test to see if the fans work, turn on your air conditioning.

Install a fan override switch. A few of us are running them now.