2nd Gen Non-Engine/Transmission Heater/AC fan speed too fast on low?

[ramcam6]

I think the cab heater runs too fast on the lowest speed. I end up having to turn it off then on etc. Has anyone put a reostat or a resistor to cut the fan speed? I don't have any problem on anything but low, however I think it blows too hard on the lowest speed. It isn't that it doesn't run as it's spec'ed, just that I'd like to have it run about 75% slower or have it adjustable on the lowest setting. Anyone done anything with their's or is this something that none have been irritated with? Thanks in advance for the expert advice you guys give so freely.



Charlie

 

[baby.driver]

There is a resistor module that is probably failing.

 

[illflem]

I've found on mine that most of the time the fan off position passes all the air I need.

 

[jchapin]

I've had the same complaint with mine too. Ideally, it would be nice to retrofit a smooth intermittant dial, but I just mess with vent directionals and fiddle with temperature dial while keeping the fan on low and have kept it pretty comfortable. Of course now that you bring it up... .

-Jack

 

[klenger]

You could slow it down when you are using the heater, but I think the condenser would freeze up on A/C if the fan wan't running fast enough.

 

[wtrenholm]

That's kinda irritated me sometimes too. But I've never thought about doing anything about it. But now that you mention it.



I think the easiest way to accomplish it would be to put a SPST switch in the fan low speed wire between the resistor block and the control head (which is tan on the 2002 diagrams). Then you could open the circuit when you want to slow it down (I guess I'm assuming/hoping there will be airflow from high pressure at the base of the windshield); close the circuit for low speed. Selecting the tan wire won't affect any other speed, as they will still have a path to ground regardless of the switch position.



The AC system has a cycling switch to prevent evaporator freeze up, so that will be a non issue.



That's my idea and for all I know it might even work. Wouldn't that be special. Now to go do it to the truck. I seem to have more plans then I have time.



Wayne

 

[ramcam6]

Thanks Very Much to Wayne and all the others who replied. I don't think there is anything wrong with my heater A/C fan. That's the way all others I have been around work. It is just that I think the way they designed it the fan blows too hard on the lowest speed. I may try and find that brown wire that wtrenholm wrote about. Instead of an on/off switch in there what about a Radio Shack reostat so the speed between low and off could be adjustable? Thanks again all!

Charlie