Yes, you can change the fan speed settings.
The fan speed control is a five-way switch.
Off-1-2-3-4
It is wired to three resistors that are connected directly to the blower motor.
4 is straight battery to blower to ground. As you turn the speed DOWN (Towards 1) it adds another resitor to the series.
The three resistors I assume are power resistors.
I don't know what wattage, but they should be located somewhere behind the glovebox.
In theory you could replace the five-way switch with one with more positions, like a 6 or 8 way.
It still needs to handle 100% of the power from the blower motor, so you need fo find out how many watts the blower motor uses.
You would then add more resistors to the series to get more speed options.
Another option as above is to use a PWM controller.
This would allow for very precise control of fan speed from zero to ~100%.
You again need to know how many watts (Or Amps) the blower motor uses, and find a PWM circuit or chip that can handle that much power.
http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=124615&Site=US&Cat=31523794
The fan speed control is a five-way switch.
Off-1-2-3-4
It is wired to three resistors that are connected directly to the blower motor.
4 is straight battery to blower to ground. As you turn the speed DOWN (Towards 1) it adds another resitor to the series.
The three resistors I assume are power resistors.
I don't know what wattage, but they should be located somewhere behind the glovebox.
In theory you could replace the five-way switch with one with more positions, like a 6 or 8 way.
It still needs to handle 100% of the power from the blower motor, so you need fo find out how many watts the blower motor uses.
You would then add more resistors to the series to get more speed options.
Another option as above is to use a PWM controller.
This would allow for very precise control of fan speed from zero to ~100%.
You again need to know how many watts (Or Amps) the blower motor uses, and find a PWM circuit or chip that can handle that much power.
http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=124615&Site=US&Cat=31523794