AC inside blower fan motor access and-or removal

[sailnimble@yahoo.com]

Our (original) AC will not run more than about a minute (90ish seconds) before shutting down. At the 2019 Westyfest West someone suggested looking at the interior blower fan motor as the blower fan appears unresponsive when starting up the AC, and there's likely a safety shutoff that's triggered when the interior blower fan fails to start up. Makes sense to me, so I finally took the ceiling grill off, that's just outside the bathroom door to see if I could get at this blower fan motor. It appears there are 2 cage-type fans, one on each side of the motor, and it's definitely not firing-up when the AC controls are turned on (see attached photo)

I also use the inspection access inside the bathroom just above the door to look at this space, but beyond finding some wiring on the left side - and a 20amp fuse that was burned out (see attached photo) - I was still unable to access the blower motor, or determine which wires might be for the blower motor.

(I'm not sure what the 20 amp fuse was protecting as the AC would still start up with out it, and after replacing the fuse the blower fan still failed to start and the AC still ran for aprox. a minute - I can't think of another system that's not working; does anyone know what this fuse is for?)

My primary ask: I'd like to get at the motor so I can put a meter on it to find out if it's getting power when the AC is switched on, possibly replace it, etc. I can't figure out how to get at this. Has anyone figured out a good way to get at this motor? Do I need to take apart the ceiling to do this? (Not an attractive proposition, unless someone knows an appropriate way to do that.) I readily admit I may be missing an obvious answer, but I right now I can't see it.

I did find this thread from a couple years back that speaks to AC shut downs, but while it was interesting and full of good info, it talked all around my question but no one mentioned how to actually get at the interior AC blower motor:

Roof AC Shuts Down

Picked up a Westi and noticed the roof AC isn't working. Plugged into shore power it will turn on and then at night within 10 minutes it's shuts off and just the fan runs. During the day less than 3 minutes of run time. (We were in Las Vegas) I tried running the generator and it seems like...

sprinter-source.com

View attachment 148776

 

[MrTomacco]

My problem was the exterior fan which is exposed to the weather unlike the internal fan. Maybe the AC started and then shut down because the exterior fan did not start in time. Just a guess here. Open the sky light and see if the fan spins freely and if it spins up when turning the AC on.

 

[onemanvan]

Lower the control panel for the A/C ( 4 screws ) and measure the voltage across the speed control rheostat R1 for the air circulation fan M1.
Assuming fuse F3 is good and relay K3 is latching and R! is fully clockwise ( fan full speed ) you should see 12~13 volts.
Also confirm motor M1 and the squirrel cage fans spin freely - maybe something got sucked into the fan housing and is binding it up.

 

[CaptnALinTiverton]

Were you trying to run the rooftop AC with the engine running or plugged into shore power? Either way, the circulation fan runs immediately as relay K3 energizes when you press the rocker switch to ON, assuming fuse F3 (25 Amp) is good. It should stay on unless the voltage drops so low that relay K3 kicks out. Offhand I don;t know where fuse F3 is located but it is in series with K3 contacts and the fan. There is no 20 Amp fuse in the AC circuitry. Perhaps someone put a 20 Amp fuse in its place and if so, it could blow every time you turn the fan but I doubt it. If you get at the fan wires, you could apply 12 volts to its terminals through a fuse as a test with its connector disconnected with the AC rocker switch off.

AL

 

[CaptnALinTiverton]

Lower the control panel for the A/C ( 4 screws ) and measure the voltage across the speed control rheostat R1 for the air circulation fan M1.
Assuming fuse F3 is good and relay K3 is latching and R! is fully clockwise ( fan full speed ) you should see 12~13 volts.
Also confirm motor M1 and the squirrel cage fans spin freely - maybe something got sucked into the fan housing and is binding it up.


View attachment 148970

I have found this schematic to have errors. I have redrawn it in accordance with the circuit board. Even with the circuit redrawn, this circuitry is very tricky and was basically impossible for me to fully analyze. I'll attempt to paste my new ski below as a jpeg; I also have it in pdf a could upload it sometime.



AL

 

[Riptide]

Make sure your condenser fan on the roof, in the forward half of the unit, is turning on. If it doesn't, the AC trips on overpressure, I think. The fan replacement is pretty straightforward, if a little hard to get to.

 

[sailnimble@yahoo.com]

Thanks everyone for the suggestions. We've been testing the unit on shore power.

There was already a blown 20amp fuse in that fuse housing, so I just replaced it with another 20 (you can see this yellow blown fuse in the photo I attached earlier) The fuse housing is just past the larger white wire housing and it appears to be in line on a wire coming out of the white housing.

I'll drop the AC controls and measure the voltage. The inside blower fan cages are spinning freely,so there's no obstruction. I'll check the exterior fan again to make sure it's spinning when it starts up.

 

[sailnimble@yahoo.com]

I dropped the AC controls housing, and was able to verify always-on 12volt current on the brown and red-black leads on top of the rocker switch (see photo). I couldn't make sense of the rest, or correlate any of what I saw with the diagrams above. I'd really like to simply get at the leads entering the blower fan motor so I can verify if current is getting that far, but I have no idea how to reach the leads, which apparently are on top, away from me. Has any one pulled this blower motor, or know of a trick for getting at it?

As I mentioned in my previous post, clicking the rocker switch on does activate the compressor on the roof (I can hear it and-or the fan), but the interior blower fan does not activate; but the blower fan will manually rotate freely. If anyone has suggestions on which wires to test in my photo, for detecting current when the rocker switch is in the "on" position, that might verify (or not) that current is actually headed to the blower motor, please let me know.

I'm still puzzled by the blown 20amp fuse I found, just inside-left, when viewing forward through the open hatch over the bathroom door - could this perhaps be the F3 fuse( 25amp)? Can someone at least verify they see this same fuse, and let me know if it is indeed supposed to be 20 or 25amp? (I did replace it with a good 20amp fuse, and after several activations of the rocker switch it still looks good.) Not being the original Westy owner, I can't say what happened with this fuse before we acquired the vehicle.

 

[onemanvan]

I've attached some more detailed wiring diagrams for the westy.
There are two schematics - the second one is for the A/C - "Wiring diagram of climate control"
For the life of me I cannot imagine why they had to make the electronics for the A/C so complicated!

It's difficult to tell but it would appear there are two blower fan motors - X310m1 & X310m2
and two corresponding fuses - F201 & F202 ( both 30 amp fuses ).

This makes no sense to me as:
1) I only see one blower fan
2) Typically only one blower fan is required to circulate cabin air through the evaporator.

It would appear that motor M200 & corresponding fuse F203 are the roof A/C fan ( condenser fan up on the roof )...

Note: under the water heater there is a black plastic box with numerous relays for the A/C - I don't remember if there are any fuses in there?

Note: In 2006 Westfalia replaced all of the A/C units with a higher BTU air conditioner - so it may be that none of the electrical diagrams we have for the A/C are 100% accurate...

Here are the color codes for wires:

 

[sailnimble@yahoo.com]

I've looked at the fuses behind the lower bench, above the water tank, but none are labeled as anything related to the AC. I don't know of any other place where fuses might be - any idea where the 30amp.fuses F201 & F202 might be?

 

[onemanvan]

I've looked at the fuses behind the lower bench, above the water tank, but none are labeled as anything related to the AC. I don't know of any other place where fuses might be - any idea where the 30amp.fuses F201 & F202 might be?

under the water heater there is a black plastic box with numerous relays for the A/C - I don't remember if there are any fuses in there?

 

[sailnimble@yahoo.com]

Found the box, its even labeled Kerstner Found three fuses inside: F3 (25amp), F4 (7.5amp), and F5 (10amp) - see attached photo. All 3 fuses tested good. Also found 8 relays, all labeled 12v 40A. These relays are also found on the diagrams referenced above. Still looking for the two 30amp fuses F201 and/or F202, as these appear to be inline for the blower motor; if one is blown, that's probably my issue. Any ideas where to look next?

 

[CaptnALinTiverton]

Again I assume you have the power supplies running (plugged into external 120 VAC power) or the engine running. If you hear a click when you turn on the AC rocker switch in the ceiling and hear other things running (like you said compressor, etc.) relay K3 is energizing in the relay box so if F3 in the box is good, your circulation fan should be running. If not, the wire to it broke or it burned out. That's all there is to that part of the circuit: K3 contacts in series with F3 and the blower. If you know the difference between voltage and current and how to measure it, you should have current in that series circuit. Otherwise, F3, K3 contacts, blower or wires thereof is bad.

AL

 

[onemanvan]

In 2006 Westfalia replaced all of the A/C units with a higher BTU air conditioner,
so it may be that none of the electrical diagrams we have for the A/C are 100% accurate...

And since there are two different wiring diagrams it's difficult to know which one might be more relevant...

This is just a guess but I suspect there is only one blower fan and corresponding fuse with the 'newer' A/C
Furthermore the fuse you already replaced might be the one for that fan.

I tried pulling the fuse on mine to see if the fan stopped but my hands aren't strong enough to pull the fuse - sucks getting old...
So I don't know if that fuse is related to the problem you're seeing - but if it is then read on:

Blade fuses usually have two tiny bits of metal ( contacts ) that you can get your meter probes on - assuming the probes are sharp and pointy.




If you see 12vdc on both contacts
then the problem is downstream from the fuse IE: motor, speed control, wiring, etc...
else the problem is upstream - IE: relay, wiring, etc...

 

[sailnimble@yahoo.com]

That fuse is indeed difficult to remove; for awhile I thought í wouldn't get it out! Awkward location made it challenging. I will try to use the meter on it and see if I get 12V

 

[onemanvan]

There are so many differences between what we see in our westy's and what we see in the electrical diagrams
that it's almost impossible to provide clear guidance by simply looking at pictures and diagrams...

However - the more I study the diagrams the more inclined I am to trust the first diagram - with some caveats - such as:

1) I see no physical evidence of there being two evaporator blower motors ( M1 & M3 ) however I am inclined to believe M1 is the motor we're interested in.

2) The relay id's on the diagrams are different from the physical markings on the relays in the black plastic box you pictured.

Nevertheless - fuse F3 in the black plastic box could be the one for the motor we're interested in.
So you should check the voltage on that fuse as well.

Same assumptions apply:

If you see 12vdc on both contacts
then the problem is downstream from the fuse IE: motor, speed control, relay, wiring, etc...
else the problem is upstream - IE: relay, wiring, etc...

Also - were you able to read the model number of your evaporator blower motor?
I would be curious to know if it is an ECM motor: https://en.wikipedia.org/wiki/Brushless_DC_electric_motor

 

[sailnimble@yahoo.com]

The mystery 25amp fuse that's just outside the rectangular black metal box that contains the blower fan motor and 2 squirrel cage fans (on the Port side) has continuity (is good) but shows no 12v current when the AC toggle switch is activated. My suspect this indicates the fuse is not related to the blower fan.

 

[junkyard_sal]

This seems to be my problem I have an interior blower motor issue. Possibly among other issues. It started working again then stopped again so I am guessing some motor is stopping and that triggers a safety switch to stop the compressor