Fan selector & Zone switch issues

[rleeds]

'97 K1500, 5.7l, automatic, 180k miles

Ok. I've read a few posts and it seems my issues aren't quite addressed.
#1: Fan works in 1 & 4 only
It drains heat through the vent on 2 & 3, but appears normal on 1 & 4.
At first the resistor seemed the culprit, but after further reading, the lowest setting shouldn't operate with a bad
resistor.
#2: Heat only goes to defrost area.
No matter where I turn the switch, the air only goes through the upper vents towards the windshield (defrost).
There is leakage into the other vents, but very little.

I'm wondering if the whole HVAC control module needs to be replaced. Sooo, what are some good diagnostics to perform. Or, is it a common problem to repair.

Ideas?
Thank you!

 

[badazzbulldog]

mine just went last night while out plowing,pull it out of dash see if it has a burnt smell to it.mine wouldnt shut down in the off position,was only going to defrost then stuck on high.had a spare one threw that in and its back working normal

 

[1997chevydriver]

Fan switch is probably bad.

As for the zone selector switch its probably the blend door actuator on the HVAC box by your right foot

 

[rleeds]

Duh. I totally forgot about the blend door actuator. It was a nightmare changing 3 of them on my Intrepid. Looks like the truck is a tad more accessible.