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Radiator Fan Control

I need information regarding the radiator fan control circuit? I have no stematic that tells me the protocol. I know there are two thermostat one for water temp and one for incoming air temp. I know there is a  hydraulic control valve. I have been told there is a low speed and a high speed. How is this accomplished? Water temp? air temp? or both? There is also a electronic control box that is mounted to the hydraulic control valve.
Mine comes on the first thing in the morning till drive about 10 miles then shuts down. Then cycles on full speed. for the rest of the day. I don't think it ever goes into low speed. How can I tell you ask? My milage has gone down by about a half a mile per gal. I also watch the dash temp gage moves up and down every so slightly.

Can any one tell me where the the water t-stat and the air t-stat are located? 

Any input would be greatly appreciated  Cheers  Karl

Re: Radiator Fan Control

Reply #1 –
Quote from: Karl Brenneman –

Can any one tell me where the the water t-stat and the air t-stat are located? 

Any input would be greatly appreciated  Cheers  Karl

Karl,
Here is an M-11 engine parts location diagram.
CUMMINS SYSTEM DIAGRAMS
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Radiator Fan Control

Reply #2 –
Karl,

I don't know if you have the same Saur Danfoss radiator fan controller that is on my 2000 U320 but I have some experience with mine. I have attached the info I received from the factory.

The charge air sensor is on top of the intake manifold towards the rear. It is identifiable by the connector shown in the documentation. The coolant sensor is on the side of the block toward the front drivers side, it has the same type of connector. It's high up on the block and can be more easily seen from under the bed.

The sensors are quite robust with waterproof connectors, I hear they rarely fail.

Unfortunately for me the chip in the controller went bad. I had to replace the controller. I replaced the sensors as well because they were inexpensive and eliminated any potential problem.

Bob
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV

Re: Radiator Fan Control

Reply #3 –
Thank You Barry, Thank You Bob
Bob, What lead you to know that your Electronic controller was bad? Can you buy just the controller and not the valve assembly. I bought a new valve assembly 6 months ago. The magnet was going bad. You cant buy just the magnet you are required to buy the valve assembly and magnetic as one.
Bob can you tell me where you bought your controller and Price?
Thanks guys for your help... Cheers  Karl 

Re: Radiator Fan Control

Reply #4 –
Karl,

I see that the only serviceable parts, according to the PDF I sent you, is the coil, coil nut and weather seal. The solenoid is proportional so I'm guessing  the ordinary on/off solenoid coil would be not applicable. I'm guessing that coil is not inexpensive.

Unfortunately for us the electronics module is non-repairable, in the PDF, and each module is programmed by the manufacturer of the coach according to predicted use parameters. I purchased mine from FOT in the $800 range before Motorcade discount. The sensors were in $40 range.

I think these controllers are common in diesel engine applications and a web search yielded many hits. I explored this avenue for several days before coming to the conclusion that the FOT price was comparable.

My symptoms were the controller putting the fans into idle mode after stopping for lunch. You can imagine what this does to the temperature gauge. It would also run the fans at high speed at start-up, when it shouldn't. I would imagine a possibility of many different failure modes.

I noticed less noise from the fans after I replaced my controller. I couldn't say that I noticed an increase of MPG but I understand the fans use around 30HP at high speed.

Bob 
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV

Re: Radiator Fan Control

Reply #5 –
Karl,

After posting and out of curiosity, I see ebay has two sauer danfoss controllers. One is for a Detroit Diesel and the other for a Thomas Transit Bus, $325 and $523.10.

I'm thinking not for our application.

I wonder if it's worth contacting Sauer Danfoss customer service for repair. I didn't do that.

Bob
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV

Re: Radiator Fan Control

Reply #6 –
Bob Thank You for the information. I think I well contact Sauer Danfoss maybe they can do a rebuild. I just bought 8 new tires so my MH budget is not doing well. Its sticks and water for the next few months. Like yours the fans come on full speed when I first start the engine in the am.
Its always something with a MH.
Thank you, Happy Fourth Of July    Karl

Re: Radiator Fan Control

Reply #7 –
Karl,

When I called FOT with my fan issue, I was on the side of the road in 106F weather with a stop engine light on the dash, it was recommended to unplug the connector to the fan controller. This forces the fans into fail safe mode and the fans go into full speed all the time. I ran like that for six months while cleaning contacts and testing the two sensors and deciding if it really was the fan controller that I needed to replace.

The only downside with the fans on high speed was the extra noise and maybe a lower MPG.

Please let us know what Sauer Danfoss has to say about a rebuild. I still have my old one.

Bob
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV

Re: Radiator Fan Control

Reply #8 –
Bob,
I just emailed Sauer Danfoss to ask them if they rebuild controllers We well see. I also have cleaned all connectors. Put a new ground strap on the controller. We are here in Colonial Willburg Va. The fan control is one of those problems that needs to be checked out on the road. We wont be leaving here till Sun. Back to Raleigh N.C. I know its not the magnet I repelaced it in the spring. So it narrows down to the controller.

Thank You for your help. Cheers  Karl

Re: Radiator Fan Control

Reply #9 –
Karl,

You are welcome.

I hope your repair turns out to be less expensive than mine was.

According to FOT, the fan controllers rarely go out, but they do. That's why they keep one in stock.

Slainte!
Bob
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV

Re: Radiator Fan Control

Reply #10 –
Thanks Bob for your help. Sauer Danfoss dose have a repair dept. Minneapolis, Minnesota I am going to send the controller, Analog air temp and Analoge water temp.. to them. I understand that you changed out your controller and both water and  air sensors my question is where is the water sensor located. I found the air but not the water. Thanks again  Cheers  Karl 

Re: Radiator Fan Control

Reply #11 –
Hi Karl,

The coolant sensor on my 2000 U320 is on the driver's side of the forward end of the block. It's easier to see from under the bed than from the ground. I think I removed it from below and inserted a rubber stopper to contain the coolant. There are several other fittings on the block there but if you found the CA sensor, the connector is the same. Just look for that same connector, the sensors appear identical until removed. The sensor body is brass but will probably be dirty.

I hope Sauer Danfoss can rebuild it.

Prosit!
Bob
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV

Re: Radiator Fan Control

Reply #12 –
We replaced our controller a couple months ago. I was having intermittent spikes in temps. after talking to FOT and disconnecting the harness and the temp stayed down that seemed to have been the culprit. Now I am wondering if the fan is staying on high because my temp remains down around 185 or under 190 all the time. My milage seems to be a little high although hard to judge completely with many variables like different routes with stop & go, running the Gen set etc. My temp is only monitored by the stock gauge on the dash and It may not be accurate but it is what was showing temp. spikes before. Any ideas on how I can tell if it is cycling as it should? Is it possible the fan needs to stay on high in the summer temps although I have been in areas that have been from the 80s and max 95 not as high as a lot of the country. Is it correct to assume that GPM will be lower in warmer weather due to higher fuel temps and the fan running on high more? 
1999 U320
Mount Dora Fl

Re: Radiator Fan Control

Reply #13 –
Thanks Bob,

I found the liquid sending unit on the front drivers side of the block next to the heater hose that enters the block. I removed the sending from under the coach the one problem is I bought two 3/8" NP plugs. They fit the air sending unit but the liquid must 1/2"NP.
So I am on my way to the hardware store to buy a 1/2" plug. The top of the liquid sending unit looks like the air sending. I hope that it is the right one.

Thanks  Karl 

Re: Radiator Fan Control

Reply #14 –
Karl,

I'm glad you found the liquid sensor.

I think there was 1/2" X 3/8" bushing reducer for the sensor to fit into the block on mine.

I think that those two connectors are only used on the sensors. The sensors are described rather completely and pictured in the attached document.

Bob
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV

Re: Radiator Fan Control

Reply #15 –
Phil,

The fan controller has been described to me as fully proportional. It will operate the fans at a speed that matches the load on the cooling system. Higher engine loads equals faster fan speeds.

My controller went out the second day of a six week trip. I had the opportunity of running to California and back with the fan controller unplugged and the fans operating at full speed all the time. The fans do make additional noise but I would say the if the generator is running, you wouldn't notice the extra fan noise. But, the fans sure blow a lot of dust in the campgrounds.

As far as MPG, it made 7.9 MPG going West and 8.3 coming East, with no toad. I suspect driving style might have as big of influence as controller operation.

Cheers!
Bob
Bob & Suzy
2000 U320 4010 SPEC
2006 Honda CRV
 

Re: Radiator Fan Control

Reply #16 –
Quote from: Beerslayer_24 –
Phil,

The fan controller has been described to me as fully proportional. It will operate the fans at a speed that matches the load on the cooling system. Higher engine loads equals faster fan speeds.

My controller went out the second day of a six week trip. I had the opportunity of running to California and back with the fan controller unplugged and the fans operating at full speed all the time. The fans do make additional noise but I would say the if the generator is running, you wouldn't notice the extra fan noise. But, the fans sure blow a lot of dust in the campgrounds.

Cheers!
Bob

I think Foretravel told me it is a 2 speed fan controller.
I could not hear the difference in either speed due to engine running.
Unplugging the controller defaults it to high speed and will lower mpg.
Dont overlook the plug connection.
I found some coolant had leaked and must have landed on the connector and it was corroded. After cleaning the pins with a dental proxy brush and using contact cleaner my leg home from Las Vegas in the heat was uneventful.
Cummins M-11 450 Engine Overheating
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"