ac/heater blower noise on 2002 Ford Windstar

Without starting but key in on position or with engine running. There's a thumping noise in dash I believe to be a blower motor (ac or heater?) or a resistor. What's the easiest way to get to it to check? Is this a costly if I need to hire someone?

Asked by for the 2002 Ford Windstar
What type of noise is it what type of pitch
A thumping noise, THUMP-thump, THUMP-thump.
Fist thump is louder than second. I don't hear it if I put the fan up on high speed.
Makes no change adjusting temp control.
Haven't messed with seeing how much heat its putting out.
1 more answer
sounds like blender actuator door. this is a small door that allows the heat and ac to flow where directed. changed mine. wasn't the easiest job in the world but only because of the space to work with. first you have to take the radio out and once its out you can see the actuator right inside the space below where radio was. easy to change from there and cant really remember price of part, but don't remember being too pissed about it so it probably didn't cost too much. really not a hard job, go for it, I had next to know mechanical ability and I successfully fixed mine.