How to check the cooling fan

E

ed53

New member
Hi all, this is my first post. My wife surprised me with a special edition kubota rtv 900 a few years ago and it has been great but it seems the fan is not working properly. Does anyone know the best way to test the cooling fan?
Thanks for any help.
Ed
 
Welcome to the forum, Ed! And what a lovely wife you must have! Certainly she has good taste in machinery! :-) You will find that the forum is a gold mine of useful (and sometimes entertaining) information and advice.

Re. your cooling fan, what makes you think it is not working? It is not supposed to run all the time, but will cycle on and off as needed for cooling. Also, the RTV900s tend to run with their temp gauges on the high side of the scale. A number of folks have replace the OEM gauges with after market models that show actual temperatures. But if it not in the red on the OEM scale, there is nothing to worry about.

But this may be stuff that you know well. So perhaps you can provide more details about why you think the fan might not be working? (If temp gauge is going into the red, have you checked that your radiator is clean, for example?)

Also, we like to see pics, so feel free to post!

Cheers,

Onfoot
 
The electric cooling fan is controlled by a relay and the motor is protected by a 20A fuse. The manual states that the coolant temp of 201f will start the motor and it will shut off when temp cools to 194f. Hope this helps.
 
cooling fan operation

Thanks guys for your input! I knew it came on at what I considered to be a high temp. I checked the fuse and pulled the led off the temp sensor and grounded it and it did not come on. So I will try batt direct to the fan and if it does not work I will get a replacement motor. I assume the lcl auto parts store could match it up. I typically do all my own work so I need to get a good shop manual, what do you guys recommend? I have 5 tractors ranging from 1940-1974 and I have shop manuals for all of them. My 900 only has 300hrs on it and so far no problems, hope it will stay that way.
Again, thanks for your help,
ed
 
I have the shop manual and parts book. I paid around $80 to a $100 for the 2. I have heard that they are available on CD for a fraction of that .I ordered my books from Messicks eqp. (on the net) and it was delivered to my door. Good Luck, Bordercollie
 
ed53 said:
Thanks guys for your input! I knew it came on at what I considered to be a high temp. I checked the fuse and pulled the led off the temp sensor and grounded it and it did not come on. So I will try batt direct to the fan and if it does not work I will get a replacement motor. I assume the lcl auto parts store could match it up. I typically do all my own work so I need to get a good shop manual, what do you guys recommend? I have 5 tractors ranging from 1940-1974 and I have shop manuals for all of them. My 900 only has 300hrs on it and so far no problems, hope it will stay that way.
Again, thanks for your help,
ed
Click to expand...

Provided that the key switch was in the "on" position, grounding the lead to the temp sensor should have picked the relay that controls the fan motor. The relay is on a separate fuse (15A). This is according to the schematic in the manual. There are also a 50A and 60A sloblo that could affect fan operation but would also affect other things as well...Not likely. As you have already said..applying 12vdc to the hot lead on the cooling fan motor will tell you if the fan motor is cooked...

Let us know the out come.
 
Ed' cooling fan

Ok guys, fan works(direct from batt). Does not work when grounding the lead off temp. Checked all fuses and they are good, all I can think is the fan relay is bad. There is a 15amp fuse that controls relay for fan, alt, and brake lgts. They all work, unless there is part of the relay that controls the fan, I am stumped. Going to call the dealer tomorrow and ask them, hopefully they will have some info.
Again, thanks for your help.
ed
 
ed53 said:
Ok guys, fan works(direct from batt). Does not work when grounding the lead off temp.
Click to expand...

I do not profess to know much about such matters (I am a mechanical blunderer more than anything else), but is it not the case that the temp. point would only have power if the thermostatic relay was in the 'on' position--i.e., the engine temp would need to be hot enough to trip the relay and therefore supply power to the temp lead?
 
If the fan motor operates with 12vdc direct (which it does) then the only thing it can be is the relay or the fuse or the coolant temp switch. (which is not the sending unit for the temp gauge). According to the schematic there is a 15A fuse for the relay and a 20A for the motor. According to the diagram I am refering to there should be a Purple wire running from the temp sw to the relay. Grounding this wire should pick the relay.

Are you sure the coolant is just not getting hot enough to activate the switch?
 
My fan rarely comes on in my 2006 900. The only time it comes on is if I have been really working it hard. High speed running on the road brings the temp up enough to kick it on but normal putting around hauling wood does not.
 
cooling fan working

Thanks guys for all your input. The fan does work when I ground the wire off the switch. Fan appears to be working fine, comes on when the gage reaches about 2/3 warm. That problem is solved, but you guys got me keeping a close eye on my U joints. They appear to be ok.
Thanks guys,
ed
 
Now ..... Back to the original entry.....Your spouse surprised you with the 900 on your birthday....SO what am I doing wrong here????Mrs Kanook surprised me with a new coffee maker (she broke the old one)...Any suggestions on where I am going astray here??????
 
If you have a testlight, you can hook it to the pos. terminal on the battery and touch the probe to the temp. sensor above the alternator. You should get a light on your testlight and the fan will come on. This will test your relay and fan together.
 
I did what you suggested. The fan came on but the test light didn't light up. So, I am guessing the sensor is bad. Thanks for the instruction.
 
As stated above there are 3 things to effect the fan basically.The relay the temp sensor and fuse.when the ignition is on it throws the relay to apply a constant 12 volts to the fan. when the engine heats up do its desired temp the temp sensor switch will activate and apply a ground to the circuit completing the connection to make the fan to come on.If you have checked the fuses and they are good it leaves the temp sensor or the relay.If you disconnect the wire from the sensor and apply the wire to ground the fan should come on.If not its the relay.It is a very basic circuit to troubleshoot.On my 2004 the sensor just went south on me.They range from 29 to 54 depending on what one you have.In the mean time i keep a close eye on temp and if i see it running a bit hot i just flip a switch I added that completes the circuit to ground and let the fan run.If you turn off they key the fan goes out.So there is no worries to run down the battery.When i get caught up with bills and such ill replace the sensor but for now the switch works fine.In fact the way I have it wired in on pigtails its set up for a duo system.It can be done manually or fully automatic. Hope my rambeling helped.
Mark
 
Down here in Florida the fix is simple. Cut the blade connector off and install an eye and bolt that sucker to ground so the fan runs all the time - at least whenever the key is on.
 
I replaced the cooling fan on my 2005 RTV900 with an aftermarket and saved a big wad. It cooled better than the oem too.. am thinking I may do the same to this 2011 model this summer. There is a thread about it on my favorite RTV forum ........ this forum., of course ;) My sensors were all fine and just made sure to wire it for the proper rotation. collie
http://www.nettractortalk.com/forums/showthread.php?t=13665&page=3
 
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I was in the same boat as the OP. Fan worked when I applied 12V directly to it, but not when I grounded the pink wire to the coolant temperature sensor. When I looked at the schematic for the coolant temperature switch relay, I found that both the trigger lead and the power lead were fused.

Fuse 12 provides trigger current to the Coolant Temparature Switch Relay on a Red/Green wire. When the Coolant Temperature Switch gets hot enough it grounds the trigger coil in the relay, which closes the contacts to provide power to the fan.

Fuse 6 provides power to the fan motor through the Coolant Temperature Switch Relay on a Red/Blue wire.

Both fuses must be in place and working for the fan motor to operate.

With the ignition on, I wasn't getting any voltage on the Red/Green wire to the coolant temperature switch relay.

In the manual, fuse 12 is labeled as controlling a work light, which my RTV doesn't have. When another fuse blew, I pulled #12 and used it as I didn't have any fuses on hand. So the first time the RTV got hot enough to need the fan, it didn't come on and the temperature gauge went into the red. Replacing fuse 12 with a new one fixed the problem.

Hope this helps somebody else out there...
 
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