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Butterball06 · 01-13-2021, 07:37 PM

Got the wiring figured out on what goes where. Here is what is going on. Fan running full speed all the time. When I disconnect and reconnect the brown - and red + wires the fan goes to idle for a few seconds then back to full. My guess is that the electronics in the Danfoss are shot. Question about installing Ron’s setup.
Can the thermo switch be installed in the radiator where the bung is located just below the hose or should the switch be put in the thermostat housing? Does it make a difference? I am looking forward to solving this issue. Thanks for the help.

birdhunter · 01-13-2021, 10:26 PM

Is that an o-ring I see in the disassembled fan controller towards the end of the shaft?

Butterball06 · 01-14-2021, 08:01 AM

Ron,

Thanks for the reply. I’ve got all the wires figured out. In starting the engine the fan runs on high. When I unplug the power supply to the controller the fan still runs on high. When I plug the power supply back into the controller the fan goes to idle but only for two seconds then goes back to high speed. Do you think it is controller failure or stuck solenoid? I will take the solenoid apart and clean to see if that helps. Do you happen to know if one of the three temp sensors in the top of the engine is dedicated to the fan controller? If so, I would guess that it will no longer be in use, therefore I would remove it and replace with the one for your setup. I do know one of the three sensors goes to the VDO gauge on the dash, I would assume one of the others goes to the Silver Leaf or ECM. Anyway, I will continue investigate.

On another subject and for those that might have this issue. When first I bought this used rig the dash coolant gauge registered high, way high, while the Silver Leaf was reading 180-185° at highway speeds. I replaced both the gauge and the sensor and the gauge still read high. On a long shot I isolated the coolant gauge ground wire from the rats nest behind the dash and grounded it directly to the vehicle. Gauge now matches the same temp as what the Silver Leaf reports.

Butterball06 · 01-14-2021, 07:16 PM

Ron,

Okay, Not totally finished with your setup. Here is my update. Direct power to the yellow and orange wires at the controller gives me the fan at slow speed. Disconnect power and the fan goes to high. Based on my trouble shooting I am pretty sure the electronics in the Danfoss controller are shot. I am mounting the DC motor controller in the last bay on the passenger side. Easier to access for adjustments.
My question: Does the thermal switch allow variable power through as things heat up, as to allow the fan to operate at slower speeds until 205° is reached, at which time fan is at full speed?

Thanks for all your help.

Butterball06 · 01-16-2021, 08:08 AM

Hi Ron,

All is sorted out, now for the road test. Since the input power to the controller is being bypassed do you think there will be any issues if the 6 pin is reconnected?
The six pin on my rig doesn’t deliver any power it is just for the sensors which I presume are no longer being used. Thanks again for the help.

Mlfiedler · 01-17-2021, 04:43 PM

Yeah, another sensor may be making things too fiddley.
As I understand the original setup, Sauer Danfoss modulated the fan speed based on temperature of coolant, intake air, and pressure in the A/C system.
If the proportioning valve goes to full speed when the voltage on this modified set up goes to zero, I thought put a second NC temp switch in the air plenum from CAC to intake, and add a NC relay, opened when the A/C triggers, to take the fan to high speed when any of the original three constraints is sensed. It is likely the air temp and coolant temp will tend to move in parallel, but it seems possible if you hit WOT on an on ramp for example, the thermal mass of coolant could hold its temp rise back, while the CAC was pumping hotter air than you want into the manifold.
However, initial testing suggested my actuator coil was not responsive. I tried direct 12v to the coil wires, and can sense no movement. My ohm-meter showed 18K ohms, which seemed like it might reflect a good coil . . . Still, I started the coach and let it idle. I connected and disconnected my wires from the 12v source to the coil half a dozen times. I put my volt meter in series, and it showed 12.65 volts. But the fan kept howling. So I gave up, and headed into the coach to kill the engine. Just as I got to the steps, it was as if a cone of silence fell over me! The roar of the fan had disappeared!

I ran back around to where I had a pigtail wire connecting the coil to my spare jump-start battery, and disconnected the wire. Glorious noise, the fan roared back to life! After who knows how many years — certainly the three we have owned the coach — the valve may have been stuck, but finally popped loose.

Just for the ducks of it, I’m going to try the “clean-all-the-terminals” fix before I start installing other components. Wouldn’t that be a hoot, if it worked as intended!

ronandsue74 · 01-19-2021, 06:58 AM

butterball06,
Sorry for not responding sooner, I've been out of touch skiing in Colorado. I'll respond later today.

ronandsue74 · 01-19-2021, 10:45 AM

butterball06, The thermal switch is just an on/off, open/closed switch it is not variable. That is where your fan controller comes in, you must adjust the voltage going to the Danfoss two wire solenoid. The sweet spot for my setup is 9.9 volts. Yours might be a little different, this allows my fan to turn just fast enough to maintain 188-192 degrees most of the time. Regarding the thermal switch location, it will be most accurate with your actual engine temperature the closer it is to the engine thermostat. However, It may be accurate enough installed in the radiator bung. That is something you will just have to test.
You can reconnect the sensor wires but I don't think they will have any effect as your original Danfoss controller is no longer functional.
How did your road test go?

ronandsue74 · 01-19-2021, 02:49 PM

birdhunter, Yes it is an o-ring

ronandsue74 · 01-19-2021, 03:00 PM

Rich, There are also two o-rings at the top of my pic. They go on the magnetic solenoid shaft to keep moisture & dirt from entering the shaft. With age they can deteriorate allowing corrosion to build up on the shaft rendering the magnet ineffective. By the way, the two o-rings are not quite the same size.

birdhunter · 01-19-2021, 10:20 PM

Ron, so where did you get the new o-rings? Danfoss? I'm wondering if a dirty solenoid or bad o-rings is what's going on with mine. If I start from cold in like 70° temperatures it'll start out pretty slow but then the fan will jump up to medium and then it might jump back down to slow. It seems to work perfectly on the highway cycling nicely.

Butterball06 · 01-20-2021, 06:35 AM

Hi Ron,

How is the snow?

Have yet to do the road test but all appears to work as designed. Curious about AC. Have you had any issues with too much pressure due to the fact the Danfoss controller is no longer in play?

On another subject. I have noticed in my exhaust setup that there is no real vibration isolation, rubber mounts, etc. There is a a so called flex section of metal pipe of about 8 inches long. Doesn’t really seem to flex that much. Any experience on this subject?

Thanks again for all the help with the controller.

ronandsue74 · 01-20-2021, 02:40 PM

The snow was only ok.
I have not had any air conditioner pressure issues. I think it's probably because my low fan speed is high enough to keep overpressure from happening.
Not as much as there should have been in the middle of January. Breck was ok Vail much better. The only experience I have with with exhaust is that the flex pipe broke right where it joins to the solid pipe. I assume from vibration & lack of flexibility. Not a big deal to fix, I just got 4" exhaust band clamps, all has been good since.

Butterball06 · 01-23-2021, 03:14 PM

Hi Ron,

Do you happen to know how hot the controller gets? As mentioned, I am mounting the speed controller in my back bay. As to keep the dirt and dust out of the unit I am thinking a plastic project box. Now I am thinking it might melt. What do you think? Still haven’t done a road test but the unit works as designed.

Thanks!