Only 3 of 4 blower fan speeds?

[Gordonr1973]

Hi guys;

I'm trying to find a gremlin in my heater/blower fan system...the 2 lowest fan speed settings blow the same in my truck. When I switch to the 3rd and 4th, there is a definite difference.

I changed the fan motor, the relay and double-checked my wiring vs the wiring diagrams listed here on the site, everything looks fine.

The only thing I didn't pull out to inspect was the control switches in the dash...any suggestions??