whirpool furnace fs643-125cr

[ddh]

the wiring diagram is missing what wires do i switch to put blower on high

[Repair-man]

DDH, could you please be more specific as to the choices of wires you have, and whether this is a gas or electric furnace. Also mention which of the motor wires are currently being used and their colors.

Generically speaking, the speed wires on most blowers are as follows:

black=high
blue=med
red=low

You can only raise the speed if the black wire is currently not connected. If it is, you're already on high speed for cooling.

[ddh]

thank you it is a gas furnace and i put a 3 ton a/c on it and coil freezes up blower sounds very slow will check wire colors today   not all the time tho thank you very much ddh