The heater was working great on my '94 Bronco until my teenage son forced the heater temp control **** a little past it's normal stop position. Now I only get cool to slightly warm air.

I thought it may have been a cable adjustment problem so I had the cable adjusted which only helped a little. Any ideas on how to get my hot air back?

 

I need to add that I also changed the thermostat recently and made sure the heater is getting hot coolant so that's not the problem.