Heater Fan Problem 71 RR

RR newbie here. My heater blower works in the ACC ignition switch position and then cuts out when the key is turned to start/on position. I cannot see how the ignition and heater fan are related on the wiring diagram. Do I have a bad ignition switch?

Also how is the horn cap cover mounted on the three spoke wheel--I do not see any screws on the back--is it held on with clips? Thanks.

I don't know about the fan, but there are three little receivers in the wheel, and three little [Edited by Moparts - Family Friendly Site - Keep it clean] on the cover that snap into them.