[rundlc]

As the title says, I have a 02 #746 The fan control on the drivers side is on the lowest setting and will not respond to higher fan control positions.

Thus far I found a clicking relay on the small relay rack behind the dash (per Newell service), I replaced the relay, no change.

I swapped the drivers side blower control wiring over to the passengers side to make sure the switch was ok, I ran the passengers side on all speeds of the drivers switch control, it worked so the switch is ok.

We swapped the two resistors that were next to all the relays no change in drivers side blower, assuming two resistors for the two blower controls, no change.

I am not sure what else to try at this point, other than rerouting the pass side into the drivers in the short term. I know that is not the fix. but it'll only be a few months before the fall is here and one definitely need to have a working defrost system to clear those windows up front. 

I am unable to check the resistor at the blower motor cause well I cant even see the thing. I am assuming there is a resistor at the motor, could be wrong on this.

I am not afraid to tear the dash down but I just have no idea how its all put together and I don't want to break something yanking on it. I've asked Creslie if there are any step by step directions, I kind of doubt it since each rig is different

Oh the joy of trying to fix things, nothing like having cold ac but not have the cool running over your face cause you cant move the air!! LOL, LOL  not funny but if I don't laugh I may cry!


Fanless in Elk Grove

[Richard]

Carthan,

I am a Southern boy, so English is a second language to me. I am not clear on the control and fan swap results. Can you clarify.

When you moved the passenger fan wiring to the driver control, what were the results?

When you moved the driver fan wiring to the passenger control, what were the results?

Thanks,

[rundlc]

Richard lol ok ill retry. 

When I swapped the control wiring from the drivers side to the passengers side the control knob worked each fan speed like it is designed to work. When doing the opposite, passengers side control wiring to try and turn the fan speed up there was no change. 

We did this for the relays and both resistors, no effect on drivers side. Passengers side worked until we pulled its relay.

[Richard]

"passengers side control wiring to try and turn the fan speed up there was no change"

Should I interpret that to mean the passenger side control wiring would not change the fan speed when connected to the drivers side fan? Yes or No?

"Passengers side worked until we pulled its relay." Please explain this.

Why do you not suspect the passenger side control knob?

I totally do not understand the diagnostics, and I apologize for that.

[rundlc]

Richard maybe what I was trying to say is I used the fan control knob from the passenger side to try and operate the drivers side blower motor. When I did that the control knob had no effect on the drivers side speed control. I then took the control knob from the drivers side and connected it to the wiring of the passenger side the blower motor worked at each speed. Sorry for not explaining it throughly.

[Richard]

You explained it perfectly, i had a mental block for some reason. Thank you for your patience. Who supplies the units to Newell? Thinking a schematic would be useful

[rundlc]

Richard no problem sir! I am not looking forward to figuring out how to "undo" everything that I am sure has to be taken apart to do this job but I don't see any other way to get to the blower motor, at this point taking a trip to the mother ship is not possible. I guess Im good until winter hits!

[Richard]

I am just thinking out loud here. All of the DC fan motors I have played with, adjust their speed by running the voltage through a resistor to vary the voltage to the motor. DC motor turns faster with higher voltage.

The fact that the motor turns may be saying this is not a motor problem.

Without seeing your setup, I can’t tell you how to do this. But I would run a quick diagnostic if I could. If you can access the two wires that lead to the motor, hot wire them to 12 VDC, and see if you get high speed. If so, then the motor is good, and you shouldn’t take the coach apart to remove it. If the motor spins at high speed with direct feed of 12VDC then the problem is not the motor.

One caveat to all this thinking is that in recent years, manufacturers have used PWM, pulse width modulation, to give infinitely fine control of DC motor speeds. PWM essentially turns the voltage on and off very quickly. I doubt you have a PWM control.

[rundlc]

   

So after talking to the guys at Newell, I decided to do a temporary fix until I decide if and when I go to the base to have this air box fan situation handled. I went to the hot rod shop and bought a few 2.5" tees and rerouted the working dash air and defrost to the drivers side.  It pretty much took me a few hours once I got the dash cap off, but now I at least have defrost, vent and floor air blowing now.

The oem air box manufacturer is no longer in business of course, so I can imagine what the cost of this repair would be if the whole unit needed to get replaced. 

For now I can live with this fix.

Onto the next project.