Several years ago I rebuilt my entire A/C system, all new parts under the hood. Excellent results with temperature at the center vent as low as 37F. But I’ve always been disappointed with the way this system distributes that nice cold air.
First the fan blower only has three speeds.
Low speed … Very low volume, which is nice
Med speed … Just a little more volume but not that much
High speed … Blows you out of your seat and is so noisy that it’s almost unusable.
So effectively you have only two usable speeds with Med being pretty wimpy and nowhere near equally between the high and low speeds.
The other problem is that you have no choice of where the air goes. The cold air is always directed out of the dash outlets AND the footwell (which also diverts some of it’s air out of the rear of the console). So at least 50% of the total air is directed where you can’t even feel it. Hey … on a really hot day I want almost 100% of that cold air coming out of the dashboard vents and going by me first on it’s way to cooling the cabin. Even the cheapest cars have that option.
So I’ve decide to modify the distribution system to deal with the “warmer” Texas weather.
First I’m getting rid of all the automatic stuff and running the system in manual. I’m changing over the three speed fan switch to variable speed using a PWM (pulse-width modulation) controller. A very slick new tech way of giving your fans whatever speed you want between off and 100%. With the added bonus of very little heat and these things are very inexpensive. This will involve pulling out both fan assemblies (argh) and a bit of modification to the existing fan switch but, bring it on.
Next I have to figure out how to command the lower blend door to close while I have the system on full cold. This will send all the air through the dash outlets.
As you can see from the diagram the only time the lower blend door is fully closed is in the defrost position, but I should be able to figure that out.
Lastly I’ve permanently fixed my recirculation doors on the two blower assemblies to the cabin air position to maximize the cooler air that’s in the cabin and not trying to cool hot
outside air.
PRAY FOR ME !
