My blower motor wont work on the high setting on my 72. Is there a separate fuse or something that runs the blower on high? It worked fine last week

Hi blower uses a relay, usually mounted on top of the a/c box towards the engine, I think it has a purple wire running from it to the blower. It looks like a hoen relay. Its probably shorted, I have seen some burn thru at the connector requiring a wire repair.

Will an auto parts store have it? What exactly do i ask for because the parts counter person wont have any idea

There should be a fuse in the heavy wire to the relay - I think that wire is orange??. Check that before you buy anything.