Blower only works on High?
 

97 F150 Blower only works on high, not lo, med, med high, just high. And when I turn it on to High it seems to suck so much power the lights flicker. Any Ideas?

This is a common problem with these trucks as I've recently come to find out.
The culprit is the "blower motor resistor"
It is just up under the passenger side dash/glovebox.
I paid $34 Canadian(taxes in) 2 days ago for the part. I think I saw them on Rock Auto for under 20 US.
Took me five minutes to change the part and the fan now works on all speeds again.
Should solve your problem.....all the best!