Fan speed switch doesn't work

[angler2]

Yesterday when I started the truck, the fan speed knob worked. I drove about 2 miles to a meeting, got out and when I got back in, the knob turns, but the fan speed stays the same. It seems like it is stuck on the high side; maybe 4.

Any tips?

Thanks,

Brad

[terryknight]

that is the default for when the controller goes south

[angler2]

How hard is it to replace the controller and what does it cost?

[tensixniner]

Blower motor resistor is most likely what you need.
When it goes bad you only get high speed fan.
It's behind the glovebox.
Try the dealer or Rockauto.com

[angler2]

Cool. Ordered one!

[angler2]

Got part from Rockauto (fast and cheap - got some filters, too).

Still no workie! Stuck on fan speed 4. Checked harness. Checked connector. Everything looked fine.

What next?