What's this part I'm missing in the red circle? Looks like a hose went there? What is it? I've seen pics of what it should be and it's some type of hose or something? Is it something important?
Thanks.

 

On my sisters GS300 there is a connection that goes to the fan on the radiator.

 

What year and model is your car?

 

Mines a 98 GS300.

 

Anyone else have any ideas what that is and what it's for? Thanks.

 

I think it's a hose to force some air to the ECU compartment for cooling purposes. I disconnected mine, and so far so good. So I think you shouldn't be too concerned about it. You can just leave it as it is, or plug it to prevent dirt etc. entering the ECU compartment.

 

It is just a breather tube. The way it works is the fans create a suction in the shroud with draw air from the ecu box. There is another tube on the bottom of the ecu box that allows air to circulate from under the ecu box, through it, and out the tube top tube into the shroud and exhausted by the fans.

It is minimal, and it's function is to dry out any condensation or moisture present in the ecu box. Most everyone with any sort of engine build or swap eliminate it with no issues. It's really more a concern in harsh cold climates or humid climates, like the extreme nothern states or states with disgusting humidity and steamy summer rains like florida.

In your pic the molded nipple is broken off the ecu box so the flex tube cannot be snapped back into place. you would be replacing the lower half of the ecu box. Disconnecting everything in the ecu box to do so. Not too hard to do, as everything just unclips and reconnects, but there is alot in there.

 

Thanks peeps. Maybe I'll just tape it closed and poke some small holes in the tape for ventilation.