Could you rephrase the question?
is your heater core plugged up or clogged or do you want to know how to turn your heater off?
no, the bearing usally go out on them. i just replaced the 1 on mine.
A blockage in the heater core is the most likely cause. This is a difficult and expensive repair.
The heater temp blend valve is located behind the dash assembly. The dash assembly must be removed to gain access.
No
What are the steps to change the heater core on a 1991Chevy S10 pickup ?
Yes.
i have a 1999 stepside s10 and they are 205/75/r15
Yes
Unfortunately it does not unplug from the switch. Follow the harness down the column and you will see where the harness disconnects.
The heater core is located inside the HVAC (Heating, Ventilation and Air Conditioning) box which is located behind the dash assembly. The dash assembly must be removed to gain access to the HVAC box.
5/8
GOOGLE!