Ok, I have been searching and searching for more info on this issue. Here is where I am at:

I have accessed the rear blower assembly and replaced the resistor. No change. I bought a couple of new relays and no change. There is power to each relay pigtail, but not on the P/W and O/B wires respectively. No power to the blower.

When I use the switch on the dash, I can hear the relay's clicking (I know that doesn't mean they are good). When the front switch is set to rear control, they don't work or click. When I use the front switch with the rear switch set to off, I hear the relays clicking.

EDIT: Ok, so I put the 2 original relays in and tested the power to the P/W and O/B and they were both powered and the fan now works on all setting from the front switch, but nothing on the rear.

Any ideas on this just in case it reverts?

Thanks!
Mike