heater and ac on 2003 Ford Escort

my heater and ac works sometimes and sometimes it doesnt. when it doesnt work it doesnt work at all. when it does work it works on all speeds. could this be a resister or relay switch? i have checked all fuses.

2 answers
I'm thinking resistor. Fairly common on these. Inspect the resistor and its wiring connector for burned/melted wires, etc.
Could be either resistor or switch. Look at both or use a test light to check the circuit. If you would like us to look at it just call me and schedule an appointment (313-562-7022). I am sure we can figure it out for you.

Larry