2008 Kia rio climate control issue.

To make a long story short a few weeks ago my blower motor resistor finally gave out
(it looked like a big square fuse to me but the auto parts store called it a resistor so
pardon my terminology if I'm wrong) so I went down to NAPA and picked up a new one
and that fixed my main issue, however previous to that I took off the AC control panel to
check the wiring to make sure it wasn't burnt or messed up. So now onto my problem,
after putting it all back together I noticed that when I turn the climate control knob
(originally)  it only blew out cold air no matter what position it was in. I traced the metal
cable to a white plastic arm that moves in one direction or another for hot or cold that's
located right beside the gas pedal. Upon trying to secure the cable so it would properly
move the arm I found that it just wasn't doing its job anymore and my question is how
do I fix this? I noticed the arm takes a fair amount of force to move it, and to keep it in
place and the cable just isn't providing that at all so what can be done? All replies are
appreciated!