This morning our heater came on at appointed time but the fan never came on even when we switched it from auto to on setting. We have a 8 yr old split system, (2 stories) & its worked fine until today. Is there anyone that can give us a few likely scenarios to try & fix ourselves before we have to call the pro?

Could be a relay,fan control,fan motor, belt if belt driven.

An 8 year old furnace likely has all the controls on a circuit board. They are tough to trouble shoot, and it take a lot of confidence in your diagnose to cough up for a new one. Check the sticky at the top of the heating forum for sequence of operations of a gas furnace. Also, is the red light flashing?

To do simple checks like this you do need some tools. A test light, a meter, or a voltage detector might be the best place to start with. I came across the niftiest gadget for trouble shooting, a voltage detector. They work through the insulation of wires. There are several brands. I have a GB Instruments GVD-505A, less than $15 at Home Depot. Touch it to a hot wire, and the end glows red. Find the doodad that lights it on one side, and not the other, and you have the culprit. You do not have to open up housings and expose electrical contacts. You are looking at where your hand is, not where the meter is. Most people are capable of doing repairs and will get it going and not get hurt if they use a little sense. The voltage detector makes it even easier.