Heater only works on speed 4 in 94 850

[95xjsport]

I have a 1994 Volvo 850 and the heater only works on setting number 4, I replaced the blower motor which burnt up, I don't know how but the original owner who happend to be a female(no offense to all you car girls out there) somehow got gum in the motor . and I replaced the switch still having no success... I am lostis there something that I am missing???

[typesix]

There is usually a series of resistors that the fan switch connects in and out to create the different fan speeds. The resistors may have burnt out after the blower motor was gummed up. The resistors are frequently placed in the fan's airstream to cool the resistors.

[95xjsport]

where approximately would these resitors be in the airstream?? near the airbox? or in one of the "tubes"??