coolant question

[firebirdfemale]

My husband and I have a 1991 Pontiac Firebird that we purchased a few months ago. It has been sitting for quite sometime, anyway we got it running and tuned up. My question is: The radiator hose has a T pipe in it, so it splits off and a portion of it runs to the heater, is there a purpose for this or do you think there was a reason to do this? The fan is also ran on a toggle switch which we can't figure out why either?

 

[Zimgxp]

Is the "t" in the radiator or heater hose? It may go to the oil cooler. The switch may be because the fans won't run on their own. A shop manual is a very helpfull tool if you are working on the car alot.