99 wrangler heater problems (can't turn heater off)

Hi all of you as most of you know it is summer time and I have a
problem when summer time comes it gets warmer and I can not turn my
fan on with out the heater being on and it can get hot at times in my
jeep and would like to able to use the fan but cannot because if I do
I would be turning the heater on also I do not know if this may have
anything to do with the heater problem but a few months ago when I was
at school I had a dash board fire and melted the heater control to
where I could not use it and so I replace it with a new used one I got
a wrecking yard but after a month after the fire and replacement
heater control was installed I got this problem am not sure what to do
I have been checking posts but I have not found anyone with the same
problem as I do so I am turning to you guys again

My rig is a 99 wrangler sport 5 speed stick 6 cylinder engine no ac

Thanks Jamie