Heater fan blows all the time

As soon as I turn the key in my '75 Duster the blower motor is running on high. The fan switch doesn't affect it, and sliding the climate control to "off" does nothing. All the other function of the climate control work (temp, vent settings, etc). I looked at the back of the blower motor and tried to trace the wires to just unplug it but I never found a disconnect point. I tried to pull the climate controls out of the dash but they only come out a little way before being stuck. I don't want to pry on the bezel any harder out of fear of breaking it.

I searched but didn't find anything like my problem.

This is my first Mopar, so I am making sure I'm not missing some obvious answer. Worst case scenario I'll re-wire it like I do my other old cars.