blower on or off nothing else

I threw out the evaporator when I replaced the heater core in my 1977 chevy 1/2 ton. Now the blower only works on high. Is there a way to temporarily rig the resistor thats inside the air distribution box so that the blower switch has its variable speed choices functioning until I can replace all of the a/c.

you must have disconeected something cuase the evaporator does not control the fan speed . when you turn the blower on it tell the fan mostlikely located underneath pasangers dash how fast to go . like i said check your wires something is not plugged in tight.

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Jon
Installer/Help Technician
---coral springs florida---
mecp certification is not always needed. I have it and it has not helped me out at all. my experience out shines it.

The high setting on the blower is direct, and does not go through the resistor.  The fact that yours only operates on high says that the resistor(s) may be blown.

I agree with magoo_ns. The resistors control the speed of teh blower motor by limiting the current . check under the dash close to the blower motor for any resistor packs . they are usually wire wound - like a giant bulb filament .