"hi" setting actually bypasses the relay.
Kinda' common; check the purple wire on the blower;
follow it down the P/S firewall & pull the wire up
the connector gets corroded;clean it up & you should have full blast again!
HTH!
D
Yes, that connector is totally unprotected, right under the hood/fender seam. Mine was the red wire I had to bypass around the connector, not the purple.