No heat from heater

I have a 1993 Altima that has no heat.
When I slide the temperature slide thing from the cold position(far left side where it stays most to the time) to the right (to make temp hot)I hear a click, click, click, pause for 2 seconds and then click click clickagain (repeats) under the radio inside the dash. If I move it back to cold it goes away. when I move it to hot or to the right It just clicks continuosly and never gets hot.

Any ideas?

There is a motor that controlls the flow valve the valve is right next to the fire wall in the engine compartment (around where you radio is) couldnt tell you off hand where the motor is tho but sounds like something with that system is binding or cracked

I have a 1993 Altima that has no heat.
When I slide the temperature slide thing from the cold position(far left side where it stays most to the time) to the right (to make temp hot)I hear a click, click, click, pause for 2 seconds and then click click clickagain (repeats) under the radio inside the dash. If I move it back to cold it goes away. when I move it to hot or to the right It just clicks continuosly and never gets hot.

Any ideas?

My guess is that your heater core is done for. inside a heater cor there are little walls that make the coolant for your engine flow through and your fan then takes the heat from the heater core and blows it through out the car... if on of those little walls breaks the coolant just circualtes through the engine and doesn't give anything to the heater core... that may be the problem and you might have to get a new heater core