Upgrading the Blower Motor Controls
Last year I did a write-up about HowTo Install New Blower Motor
. At the time I noticed that my "Blower Motor Resistor" was in need of replacing. Here's the resistor.
A new resistor was around $25. Instead of replacing the resistor I started doing some research with an idea in mind. Start with a schematic of the A/C-Heater system electrical.
I read that the Blower Motor Resistor is part of the speed control for the blower motor. The Front Blower Switch has four positions. Hi, Med Hi, Med Lo and Lo. The way it works is that when the Blower Switch is in any of the lower three settings, resistors are added to the electrical circuit that powers the blower motor. The resistors convert some of the power flowing through the circuit into heat which in turn means there is less power to make the blower motor rotate so it spins slower.
When the switch is in the "Hi" selection the resistors are bypassed and all the power goes directly to the motor so it spins faster than the other selections. Conversely when the switch is in the "Lo" position then all of the resistors are included in the circuit so the motor now turns the slowest. I'm sure there's a more technically correct way to describe this but hopefully my version is clear enough. It's not like there will be a quiz later, thank goodness.
While this system has it's advantages there is one big disadvantage I can think of. Since the resistors are converting the electricity into heat they must be cooled. This is done by placing the resistors just downstream from the blower fan in the air ducting. This way whenever the resistors are being used they are also being cooled by the fan. But what about when you're using the Air Conditioning? That means you might be burning gas to produce electricity that's being converted into heat inside the ventilation system which is just that much more work the air conditioning compressor has to do remove that heat and again you're burning gas to produce that extra work.
Didn't know this before and if this was a regular van I would have just replaced the Blower Motor Resistor and from now on only run the fan on "Hi" when the A/C is on. But since this is Hal The Van I started looking around for ideas and got one from Erik at BadgerTrek
. Erik wrote the he had replaced the stock blower motor control with a Maxx Tronic 30 Amp PWM DC motor controller. PWM stands for Pulse Width Modulation
and it's a more energy efficient way of controlling DC motor speed. With this unit in place of the original controller Erik is able to run the blower from the house batteries when camping. This gives him powered ventilation without having to cut a hole in the van for an extra fan.
I don't know how Erik wired his system up so from here on all the ideas, either good or bad, are mine. Here's the unit I bought. I just checked on-line and it looks like it has been replaced with different model. It cost about the same as a new Blower Motor Resistor.
I'll probably mount the Maxx Tronic board within the dash so need to open it up and look around. Here's how to open the dash. There are two screws above the instrument cluster and under the top edge of the dash. Remove these.
Use something thin and flat to pry forward the edge of the instrument cluster from in front of the center cluster.
Once it pops open, pull the right edge of the instrument cluster away from the dash.
Then reach in between the two instrument panels and pull the center panel forward till it starts popping out. Take you time so not to crack it.
Work your way around the center panel.
I also removed the dog house before I started.
Got it all pulled free.
Remove the wires from the back of the cigarette lighter and the power port.
That leaves the sub-panel with the heater and A/C controls. Don't know the the official name is so I'll just call it the Climate Control Console (CCC).
Use a 9/32 socket to remove the CCC.
Then use a 1/4 socket to remove the vent selector switch from the CCC. This switch has vacuum lines attached. Unplug the other three wire connectors from the back of the CCC.