no heat blower temperature gauge

I have a 94 325is that has no heat. The blower does not work in any position. I have read on this site that if the blower works in positioin 4 the resistor needs replaced. Could this be my trouble also? What is the normal operating range on the temperature gauge. Mine does not get above the blue on the left side of the gauge. Could this be a thermostat problem, if so where is the thermostat located?

Thanks to all!
This web site is a wealth of information.