Fan thermal breaker replacement

**SteveS** · 05-10-2014, 01:17 PM

Rather frequently the complaint comes up that the radiator fan shuts off shortly after it comes on and never stays on long enough to cool the engine down. The culprit here is usually a thermal breaker that is in the voltage feed to the fan motor. This breaker is in there to protect the fan motor if it should ever stall out, which would burn out the windings in the motor. This can happen if a stick gets jammed in the fan blades or if the fan should be running while the blades are underwater. The factory breakers tend to be on the hairy edge of being adequate for the task. Another reason this might be an issue is a fan replacement with a slightly larger motor or higher current draw than stock.

Hopefully, the pictures below are self explanatory. If you have questions or comments please feel free to reply.

**Lee Pedigo** · 05-10-2014, 02:27 PM

OK...I'm going to try and locate the stock thermal breaker. Nothing directly behind the battery in the box. Must be in that mess just to the right of the battery. Thanks Steve for all of your help. I'll let you know how it works out.

**SteveS** · 05-10-2014, 05:35 PM

Originally Posted by Lee Pedigo

OK...I'm going to try and locate the stock thermal breaker. Nothing directly behind the battery in the box. Must be in that mess just to the right of the battery. Thanks Steve for all of your help. I'll let you know how it works out.

I believe that it is within the wiring harness bundle behind the battery. It will be wrapped up in the tape around the harness, just like the place shown in the picture is. Look for a lump that looks like a snake digesting its meal :-)

**Bumpers** · 05-10-2014, 11:07 PM

Definitely a issue on my rhino.. fan runs like 15 seconds at a time

**Lee Pedigo** · 05-12-2014, 08:49 PM

Okay got the new 10 amp circuit breaker hooked up and I'm going to call this a success.... fan will run and will not go out after 20 seconds like before. I took the battery out and was preparing to remove the battery box itself to get to the wiring behind it's at that time I just happened to glance down and see the tip of it in the far right front of the battery box it was uncovered by quarter inch and I saw it... saved me a lot of hassle so it's way up front corner I got lucky.

On another note the fan is acting a little different it seems to run at half speed when it first starts out and then kicks into a high gear I can't remember which speed it Ran at before but I don't remember it doing this. But all in all it's working as advertised as SteveS said it would.... thanks a bunch man.

Sent from my iPhone 5 using Tapatalk

**SteveS** · 05-12-2014, 09:58 PM

Looking good! You might want to wrap up the exposed metal on those spade lug clips with electrical tape (heat shrink tubing around each clip would be even more durable), else you might have sparks down there some day :-)

**Lee Pedigo** · 05-12-2014, 11:07 PM

Yea...I wrapped them up good and left the circuit breaker exposed like you said. I'm thinking the fact that the thermal breaker was exposed and it had a hole in the corner probably didn't help things. Any idea's on the multiple speeds of the fan. Worried that it might be a spike or drag in the electrical system. I do have to road test it still but boy did it cool down fast since the fan can stay on.

**SteveS** · 05-13-2014, 09:14 AM

Originally Posted by Lee Pedigo

....... Any idea's on the multiple speeds of the fan. Worried that it might be a spike or drag in the electrical system. I do have to road test it still but boy did it cool down fast since the fan can stay on.

Just a thought here. It is an aftermarket fan so I really have no idea if it has a 'special feature'. Perhaps you could find literature on that make to see if they have anything to say about it. It could be that the kick into high speed was tripping the original breaker? I would not worry too much about it affecting the electrical system on the machine though. If you had a voltmeter hooked up you could monitor what happens to the system voltage at run-time.

**warbee** · 01-10-2020, 08:07 AM

Guys, thanks for these. Really helped me located the Thermal Switch on my 2005 Rhino. Was buried up by the steering colum. Hope you guys don't mind that I shared both your posts on RhinoForums.net as I was unable to find this on their sites and thankfully I googled and this post came up. Really appreciate it as it save me some time in troubleshooting.

Larry

**TS2** · 07-04-2020, 04:30 PM

Hello

I did this mod yesterday on my 05 660 .. i run full gauges and before in low 90"s my 660 would run around 195 to 205 on the temp gauge , the way i would get it to come back down to 180 is that i would turn on the heater and my other water pump for the heater and it would bring it back down to 180 .. I installed a 20 amp reset fuse and now it runs at 180 all the time when it get to temp . the fan runs now before on and right back off again ..

Jake