Community Forums

macraekw · 04-19-2014, 01:02 AM

I have been experiencing a recurring overheat condition which we have been trying to resolve. The radiator was replaced; we replaced the hydraulic pump which drives the radiator fan, double-checked the coolant level and yet, it still over-temped on a recent local trip. The local Cat service center has diagnosed it as a malfunctioning radiator fan control module. They have contacted Country Coach and can't seem to locate a replacement. Has anyone else experienced this and do they have any advise how to locate a fan control module? Thanks.

palehorse89 · 04-19-2014, 01:08 AM

Read this thread http://www.irv2.com/forums/f112/radi...on-170550.html , might get you started in the right direction......
Also: http://www.irv2.com/forums/f26/fan-c...er-172449.html

2 Stroker · 04-19-2014, 09:04 AM

Call Kevin, he should be able to help, X Country Coach tech
Kevin Waite, K&M MOBILE RV REPAIR, LLC, is electrical and Mechanical Certified. Phone: 541-998-8132 (Hm); 541-953-6162 (Cell); Email: kvn.wt.7629@gmail.com.

2 stroker

dons2346 · 04-19-2014, 10:52 AM

Berendsen Fluid Power also has them. You will need the exact part number as the modules are programed by Sauer Danfoss for a specific application.

macraekw · 04-19-2014, 11:30 AM

I think I figured out why it didn't overheat on the uphill route outbound and why it overheated on the return trip back down which is mostly down hill. The side draft radiator is on the driver's side and on the way up heading North, we had a real stiff wind from the West which was probably cooling the radiator even though the fan wasn't. However, on the way down heading South, we didn't have that airflow across the radiator since the wind was still out of the West. Does this make sense?

Skip426 · 04-19-2014, 11:53 AM

Air flow from wind , keeping temp in check, would be questionable; considering engine heat on a climb. If the controller is erratic , it could have come on with a rapid temp change on the climb, vs, a slow rise, in temp, on the coast downhill.

IASM · 04-19-2014, 03:54 PM

A couple things come to mind. Are you using just the gauge or do you have a second system like silverleaf to confirm the temp. Also I had a 05 9 cat that had off and on temps and it turned out to be one of the two thermostats was sticking. Im not sure what engine or age but the thermostats do go bad and cause variable temp by not opening all the way.
Rod

phays · 04-19-2014, 04:50 PM

I assume CAT has ruled out thermostats but as suggested that is a good place to start.

You need to know which type of fan controller you have. If it is a Sauer Danforth then you may only have sensor problems. This controller uses 3 sensors; an air sensor in the turbo charger air, a coolant sensor and a switch on the dash over the road a/c compressor. I had both temperature sensors go bad.

In addition to searching the threads in this forum, try the Yahoo CC owners forum. Lots of information over there on this topic.

It would help us if you told us your model, year, and run number.

macraekw · 04-19-2014, 05:32 PM

Thanks. I'll have to call the CAT dealer on Monday to get the manufacturer, model and part number. I also presume that they checked the thermostats but I will ask. How do they determine if it's a sensor vs. a module? Don't know the run number as it is in the shop but it is a 2005 Allure 470

Quote:

Originally Posted by phays

I assume CAT has ruled out thermostats but as suggested that is a good place to start.

You need to know which type of fan controller you have. If it is a Sauer Danforth then you may only have sensor problems. This controller uses 3 sensors; an air sensor in the turbo charger air, a coolant sensor and a switch on the dash over the road a/c compressor. I had both temperature sensors go bad.

In addition to searching the threads in this forum, try the Yahoo CC owners forum. Lots of information over there on this topic.

It would help us if you told us your model, year, and run number.

HoleInOne · 04-19-2014, 06:46 PM

Fan Control Modules are available from CC. Around $700.00 with a 4-6 week wait. If you unplug the module the fan will default in the high speed setting. This will cool the engine but hurts fuel mileage. How much I'm not sure. There is a test procedure to go through to determine if it is the module or sensor. Should be able to get that on the yahoo site. I have also heard of people taking the module apart and cleaning it to fix it.

cowrv39 · 04-19-2014, 06:54 PM

When I owned my former rig I had high temps off and on. I was so frustrated that I or Freight-liner could not fine the source of the overheating. So while i was in Ok, OK I finlly took in to the Freight-Liner truck repair facillity and they found a cracked thermostat. They other repair facilities could not find the problem. They replaced it at no charge and I was problem free until I sold the rig. Hopefully your repair facility physically checked the thermostat. I had problems on slow climbs and higher elevations that were flat. The hill climbing I learned just to down shift and keep up the rpms while watching the temp gauge. Good luck in finally get your problem resolved.

smlranger · 04-19-2014, 07:07 PM

My previous DP had a CAT. I believe all CATS have two thermostats and CAT generally recommends replacing them every three years or so. If no one has checked the T-stats, I would have that done before spending more money on other stuff.

macraekw · 04-19-2014, 07:40 PM

Quote:

Originally Posted by HoleInOne

Fan Control Modules are available from CC. Around $700.00 with a 4-6 week wait. If you unplug the module the fan will default in the high speed setting. This will cool the engine but hurts fuel mileage. How much I'm not sure. There is a test procedure to go through to determine if it is the module or sensor. Should be able to get that on the yahoo site. I have also heard of people taking the module apart and cleaning it to fix it.

Thanks very much HoleInOne. As the coach is in the CAT dealer currently, I am not in an emergency situation but I wouldn't have a clue how to unplug the module. From what I've read, it sits on top of or near the radiator and I wouldn't have the foggiest idea of how to get to it if I were on the road. Any advice just in case?

phays · 04-19-2014, 08:10 PM

You can check the sensors by pulling the connector at the fan control module. An ohm meter can be used to check the resistance of the two temperature sensors. If you have the six pin connector on the fan control module then pull connector and measure resistance between pins A & B, C & D, and E & F. A to B should be close to zero ohms. C to D and E to F should be 25 to 100 ohms depending on the temperature. Lower temperature will have lower reading. In my case, both temperature sensors failed and showed an open circuit.

I ordered both sensors from Berendsen Fluid Power in Atlanta but they have locations throughout North America. In my case, the sensors were part numbers 1090173 (water) and 1090174 (air). I also ordered two connector kits just in case the originals were destroyed during replacement. They are part number K23426. Total cost was about $84.

If you remove the power connector to fan control module, the fan will run at high speed all the time. You can do this in an emergency to get you home should be running into frequent overheat issues. You'll suffer fuel penalties but at least you won't overheat. You may also be able to make the fan run at high speeds by turning the dash air control to max cool. This will close the pressure switch on the compressor forcing the fan to high speed.

On my 2000 Magna, the charge air cooler sensor is on the duct from the turbocharger to the charge air cooler on top of the engine. The coolant sensor is someplace behind the overflow tank for the engine coolant.