engine motor fan not working

[Lionel blain]

HI: my name is Lionel and I'm new to these forums, although i have read most of the post regarding my particular problem. The motor is a 400ISL cummings,

my question relates to the sauer- danfoss PWM engine fan control, mine is not working, surprise, although the solenoid coil on the hydraulic valve works great,so the fan motor slows down and speeds up when I put power to it,I was wondering if I could take the signal from the ECM and hook it directly to the solenoid to control the fan, the signal is 14 volts dc, when motor is cold, but im not sure if it just modulates as the temp rises or if it is off/on, as I could not get the motor up to 200 degrees. Any thought on this would be greatly appreciated.

 

Thanks Lionel 

[DavidL]

What's not working?

[Lionel blain]

 

the saurer danfoss PWM control for the fan motor. The solenoid and hydraulic motor for the fan all work OK.

[DavidL]

Meaning what is it not doing that you think it should be doing?

[Lionel blain]

the control for the motor radiator fan is not being controlled at all, it runs wide open because the sauer-danfoss control is shot, I'm just wondering if I can use the signal input from the ECM to control the hydraulic spool vale to the v

fan motor

[Mark Holt]

Call source engineering in Oregon and get the Thermal valve kit they Mfg for Monaco. Best thing I ever did for my Signature 

[waterskier_1]

I seriously doubt that the ECM circuitry can provide sufficient current to drive the "solenoid".  You would likely burn up the whole ECU - not good.  I'm not clear on what you have, since I'm not familiar with PWM (Pulse Width Modulation) engine fan control, nor a solenoid control hydraulic valve.  I'm thinking you have the solid state (electronic) FDCA Fan Drive Control.  Most people are replacing that unit with the original-type wax valve mounted on the radiator.  The FDCA was supposed to be far superior, detecting accelerator position, boost, barometric pressure and other things, in order to predict (proactively) the need to raise or lower the fan speed BEFORE the temperature had time to change significantly.  But the implementation was poor.  As Mark mentioned above, Source Engineering (founded by two ex-Monaco employees) recognized the problem and developed a conversion kit to wax valve control.  

  -Rick N.

[Lionel blain]

Thanks Mark, i already reached out to source engineering and the wax valves are on backorder at this time,as I am in Canada it is a lot harder to get things done.

Waterskier, thanks for the reply, I was just wondering if anyone has tried using the signal from the ecm to power up the solenoid, as it puts out 14vdc not sure on the amps but could always run through a relay to drop amps, so as not to harm  the ecm, just a thought.

[Chad A]

Get the wax valve from Source. Mine was doing the same thing and that wax valve kit made it work like a charm 

[Lionel blain]

thanks Chad, seems like that might be the only way to go,to bad cant use the control power from ecm.

[vito.a]

Many of us have had the electronic fan control module fail.  I purchased and installed a Sauer Danfoss wax valve mechanical fan controller.  

This thread has a wealth of information on replacing the electronic fan control with a mechanical wax valve: https://www.irv2.com/forums/f115/fan-stuck-wide-open-376611.html

[Lionel blain]

Thanks Vito, I have already  looked at that link,same thing, sounds like a wax valve is the solution

[Happycarz]

Monaco used more than one way to control the fan, a couple differ modules, and a single two wire pintle valve controlled by the ECM.  Mine is the latter.

I have an ECM FAN CONT SIGNAL wire going to a single solenoid/pintle valve. In the wire loom is a ECM FAN

CONT RETURN wire that is cut and not used. No one bothered to even put a piece of tape or butt connector on it.  So, I did.

Lookin at the solenoid/pintle valve, where the ECM FAN CONT SIGNAL wire is attached, I follow the other wire to see that it goes to frame ground.

I would tend to think we were beta testers for the cooling fan controls!

 

 

Edited June 26, 2023 by Happycarz
Verbiage

[Ivylog]

Twomed made his own controller 13 years ago out of a relay and a temperature sensor.

The Temp sender is a Summit Racing part # PRF 30110 200 degree sender. It is a N/O switch so open when below 200 then it closes and provides the ground for the relay. It stays closed until 185 then opens again. This just turns the fan on and off hydraulically by actuating he existing solenoid switch... the round thing with the big nut on the end. 
The relay is to provide the amps necessary to move the ball in the current solenoid… protect the temp sensor added to the engine. I found this on EBay.

Edited June 26, 2023 by Ivylog

[Lionel blain]

Thanks happycarz,mine is a 3 wire,so a little diff. yes I agree we were the beta testers and had to pay for the pleasure.

 

Ivylog, yea i was thinking of the same thing, just not sure where in my 400 motor to hook up another temp sensor. Did you hook up you ac to the relay as well so the fan would go to high when activated?

[Ivylog]

I haven’t done this mod and my dash AC has its own electric fan on the condenser mounter behind the front axle.

Amazon has a better price on the Tstat.

[Jdw12345]

I chose to go with a new Danfoss controller from Brendenson Fluid Power, I felt that there is other requests for more fan activation than engine coolant temps.
I have opened up the engine access in the closet going down the interstate with 80*-90* outside temps to observe everything under load, it’s interesting to witness the fan actuation while at road speeds. I’m sure the wax valve does the same thing.

 I have the three wire system, one of those wires is hot all the time for some reason!

Edited June 27, 2023 by Jdw12345
Added picture

[Flyinhy]

I ended up making my own too. I have a digital thermometer that sends a signal to the coil. 

[Ivan K]

On ours, the fans are managed based on coolant temperature as well as AC compressor state and intake manifold air temperature which I did not know until recently. Maybe something to consider for diy solutions, I bet it would be quite easily doable. Not sure if the wax valve conversion even with needle bypass takes intake manifold into account. I suppose not since the temp mismatch would only be large if flooring it with engine cold, which most of us would likely not do.

[Jdw12345]

That’s why I chose to go with the Danfoss controller Ivan, there’s other cooling needs besides coolant temps.

[Bill R]

@Lionel blain I took a similar approach as you initially were thinking.  I am attaching a link from irv2.com that I employed.  Also attached is a white paper on it.  Basically you replace the Sauer Danfoss PWM with a Motor Controller PWM and use a thermal switch as a safety WAO if the engine temps get too high.  The motor controller is stepping down the voltage to the control valve to run at a set pressure that will vary as the engine RPM varies for proportional control.  I have mine set to 9V that keeps the engine around 190F for fairly flat terrain.  You would have to vary for you engine to find that sweet spot and engine temps you want to run at.   I do not run my dash AC when first starting the engine at idle.  Once on the road I will turn the dash AC on.   I also ran wires to the RRB where I mounted the motor controller. I have been using this for over 2 years.  Let me know if you have any questions.

https://www.irv2.com/forums/f258/sauer-danfoss-fan-controller-option-500058.html

 

Hydraulic Fan Drive Controller Repair Option.pdf

[waterskier_1]

16 hours ago, Flyinhy said:

I ended up making my own too. I have a digital thermometer that sends a signal to the coil. 

Does your home brew controller modulate (vary the speed) of the fan or is it simply On/Off?  

  -Rick N.

[waterskier_1]

15 hours ago, Bill R said:

@Lionel blain I took a similar approach as you initially were thinking.  I am attaching a link from irv2.com that I employed.  Also attached is a white paper on it.  Basically you replace the Sauer Danfoss PWM with a Motor Controller PWM and use a thermal switch as a safety WAO if the engine temps get too high.  The motor controller is stepping down the voltage to the control valve to run at a set pressure that will vary as the engine RPM varies for proportional control.  I have mine set to 9V that keeps the engine around 190F for fairly flat terrain.  You would have to vary for you engine to find that sweet spot and engine temps you want to run at.   I do not run my dash AC when first starting the engine at idle.  Once on the road I will turn the dash AC on.   I also ran wires to the RRB where I mounted the motor controller. I have been using this for over 2 years.  Let me know if you have any questions.

https://www.irv2.com/forums/f258/sauer-danfoss-fan-controller-option-500058.html

 

Hydraulic Fan Drive Controller Repair Option.pdf 310.93 kB · 6 downloads

I just did a cursory review of this document, and it appears to just set the fan speed at a single speed, that by trial and error, will keep the coach at a desired temperature (i.e., 9.9 volts for 190°F).  Also, there is a "fail safe" that will turn the fan on maximum if some temp is exceeded.  This seem to be very rudimentary, without any temperature input (other than fail safe).  In essence, this is a single fixed speed motor running at the same speed when at ambient temps from -20°F to well over 100°F, for coolant temps of 32°F to potentially 250°F (not accounting for the engine thermostat which would prevent circulation through the radiator until around 180°F or whatever value thermostat you install).  

It seems to me that the old wax valve would be a much better choice, since at least it varies the fan speed based upon coolant temp.  I realize that the wax seal doesn't take intake manifold air temp, A/C state or barometric pressure or turbo boost into account in an attempt to anticipate (be proactive) potential increase in engine work requiring additional cooling or vice versa.  

I've had the wax valves on my 97 Dynasty Cummins C8.3 and my 05 Exec Detroit Diesel (I don't think Monaco used the FDCA on DD Series 60 engines).  The main complaint I have is that it seems to me to take a long time for the fan to lower the speed when driving under light conditions or idle after running down the highway.  I tend to stir up a lot of dust when driving off pavement because the fan is still at a higher speed.  That doesn't happen when I drive it after a full cool down (like overnight).

Something to consider,

  -Rick N.

[Bill R]

3 minutes ago, waterskier_1 said:

In essence, this is a single fixed speed motor running at the same speed

The fan speed WILL change (not fixed) as the RPM of the engine changes.  I have used a tachometer on my fan at higher engine RPM's.  For example, Engine @ idle -  Fan @ 850 RPM, Engine @ 1200 RPM - Fan @ 1400 RPM, Engine at 1400 RPM - Fan @ 1650 RPM.  As the RPM of the engine goes up, the hydraulic pump RPM increases and in turn increases the hydraulic flow & pressure and in turn the speed of the fan.   This is why in Texas and it is 105F outside, the engine temp still stays around 190F and not WAO.   Another advantage is you can adjust the fan speed for any climate temps you are in.  By just adjusting the motor controller output voltage you can set your fan speed for very cold climates or burning hot climates.  Hope this helps providing a better explanation.

If you read the irv2 post, there are many coaches running this set up.  Costs about $100 and no retrofit to the coolant piping.  Just another option to consider.

[waterskier_1]

1 hour ago, Bill R said:

The fan speed WILL change (not fixed) as the RPM of the engine changes.  I have used a tachometer on my fan at higher engine RPM's.  For example, Engine @ idle -  Fan @ 850 RPM, Engine @ 1200 RPM - Fan @ 1400 RPM, Engine at 1400 RPM - Fan @ 1650 RPM.  As the RPM of the engine goes up, the hydraulic pump RPM increases and in turn increases the hydraulic flow & pressure and in turn the speed of the fan.   This is why in Texas and it is 105F outside, the engine temp still stays around 190F and not WAO.   Another advantage is you can adjust the fan speed for any climate temps you are in.  By just adjusting the motor controller output voltage you can set your fan speed for very cold climates or burning hot climates.  Hope this helps providing a better explanation.

If you read the irv2 post, there are many coaches running this set up.  Costs about $100 and no retrofit to the coolant piping.  Just another option to consider.

Yes, you are correct that the fan speed will vary with engine RPM as the pump speed varies.  But that speed has absolutely nothing to do with the coolant temperature.  The fan will run the same speed at the same RPM in 0°F Colorado Winters as it does in your 105°F Summers in Texas.  Most users want the fan speed to reflect the coolant temperature and not the engine (or transmission) RPM.  

I have not looked in the conversion costs, and I'm all for saving money and DIY, but only when the functionality is not degraded or lost completely.  Just IMHO, others may differ.  I just wanted to bring to others attention that this "hack" doesn't provide the functionality that existed and which I think most would want to remain.  

  -Rick N.