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Fan Not Working - Overheating - Please Help! Ride Coming up!

42177 Views 20 Replies 7 Participants Last post by  harrassment
Hello guys. New member here from NJ. I have a tech question.

First off, I have a Green 2002 Grizzly 660 that I bought used off a friend. We do pretty rough mountain trails in West Milford, NJ (the old Jungle Habitat property). It is in great mechanical shape, thought the body has it's share of zip tie stitches and repairs :)

On our last ride, the moment I got home the temp light came on and I noticed that my fan wasn't operating. I pulled the plug going to the fan and there was no power when tested with a test light. I also checked the plug going to the bottom of the radiator and it is attached. Has anyone had this problem before? Anyone have any ideas as to what to check for?

I am thinking it is probably a loose wire. It was a pretty rough ride. I even cracked on of the headlight housings during an ill fated wheelie.... the rear right tire was a little flat and as soon as the front came up, the Grizzly veered off to the right into a bush.

I was looking into getting the Grizzly repair manual on CD off of eBay, but I wasn't sure if it was any good or not? Does anyone have it? Any ideas or comments?

Thanks in advance,

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Grizzly NJ, first there wont be any votage comming out that wire you tested unless the engine is very hot when you test for votage as the regulator going into the enine block acts as a switch only activated by tempeture. If you tested while the engine is hot and still no current it could be that thermocople that is plugged into the engine has gone bad (although I have never heard of this).

Also, make sure you clean the radiator of all mud and debre that may be restricting the air flow to the radiator. Other than this I have no idea what it could be.
Yeah, I did the test right away after my ride. The engine temp light was on, so the fan should have been on, but no power. The overheating and temp light coming on is a direct result of the fan not working. If the fan came on, I am pretty sure everything would be OK.

So my problem is the fan, not the overheating. I am assuming it is an electrical problem.

I downloaded the repair manual off the web about a year ago. I still have it in my computer. If I can figure out how to do it I'd be happy to send it to anyone who wants it.

It's for an 03 but I think they're all pretty much the same.
You can email it to me at [email protected] I have DSL so a large file would not be a problem.

Otherwise, we could send it via AIM or something.

That would be great. Thanks.

Did you check the fuses
Grizzly NJ:

OK here we go stay with me, this is right from the Grizzly Manual.
* first you want to check the main fuse and make sure it is good.
* If thats good you want to disconnect the fan motor and hook it up to a 12v battery. Neg on battery to black wire on motor/Pos on bat to the blue wire. No of corse it does not turn you need a new motor if it does we move on.
* If motor turns you want to check continuity on the ciccuit breaker wich runs the fan motor(located right behind the airbox and on the left side of the frame)

But then again maybe you allready have the manual...lol Just trying to help

Guys, thanks for the help. I should have mentioned I already checked the fuses and they are all OK. The main fuse I didn't pull, but if that went, nothing would be working right??? It wouldn't even start then????

OK, next... I don't have the manual... so that info os great. That was going to be the next thing I was going to try, hooking the fan wires up directly to the battery. I need to dig out my jumper wires and I was gonna do that this weekend.

If I hook the battery up directly, then that definately means the fan itself is bad and the whole fan assemply need to be replaced? What would have caused that? It was fine for the ride and just died as I got home. Maybe bad timing? OR good timing as I could have been miles into the woods.

If it works when hooked to the battery, I will need guidance on that. I will advise when I get to that step.

Again, thanks for the help. By the way if anyone has the manual in an emailable file that would be great.

Grizzly NJ,

To answer your question on if the whole fan assembly needs replacing, im not real sure. It all depends how you can get it from Yamaha. Im sure they will only sell it as a whole fan and motor assembly to ask more money.

As far as the main fuse, I would think your right as in killing power to the starter and all, but I was just reading the steps as they went out of the manual for you.

Be waiting to hear how it goes and continue if needed :)
I tried e-mailing the manual, couldn't connect with the server. I'll try again later.
I tried e-mailing the manual, couldn't connect with the server. I'll try again later.
I got the manual now... thank you very much everyone.

I will be working on the Grizzly this weekend hopefully (NFL Playoffs may get in the way) so I'll let you know what happens.

Thanks again for all the input!


PS Any NJ riders interested in hooking up for some rides, let me know. We have a pretty cool route.
OK. Here is the update. I hooked the fan up to 12V and it worked fine. Next step in repair manual said to check the "circuit breaker" and it gave a diagram of where it should be. I believe the manual is for an '04 and I have an '02.

I couldn't find anything where it said the circuit breaker should be, so I am thinking maybe it changed a bit. Very close, there are what appear three relays, two identical black ones and one white one. Are relays and circuit breakers the same thing??? I swapped the black relays and started the motor and let it warm up and the fan still did not work.

So, here I am.... I may not have been looking at the correct thing anyway, but if I was, is the white relay the one that controls the fan? Anyway to test it? If I am looking at the wrong thing, can anyone tell me where the circuit breaker is??? I checked the wire going to the electrical "box" or area and it seems ok. I cannot find any other part that may be wrong.

Next on the step is to check the thermostat or sending unit that is in the radiator. I'd like to avoid that if I dont need to remove it. So I would like to be certain on the circuit breaker check before the next step.

Anyone know or have experience of what to check?


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OK... I think I finally have it!!!!

I found the circuit breaker (small thing in a bag wrapped in electric tape... not a relay at all). Anyway, it tested fine. The next and final step in the manual says to remove the thermo and do a heat up cool down test by boiling it in water. Well, I decided to check a different way:

Since the thermo is just a switch, designed to close the circuit when it gets hot enough, I disconnected the plug from the thermo and jumped + and - wires of the plug. My theory is that if the rest of the system is OK, jumping this plug should turn the fan on, and it did! So, with that test, I assume that the rest of the system is operational and the only problem is that the thermo is not working as it should.

Just posting to let you all know, in case anyone else has this problem. Now that I know, it really isnt a big deal.

We are getting 2 feet of snow this weekend and it is frigid out. I have to brave the temps and get this fixed in the cold so I can have a good time this weekend!

Thanks for all the help.

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Hey good to know you found the problem no its time to get the part and go riding.
Yes it is... been three weeks this weekend. We're getting a blizzard and two feet of snow though, so I probably wont go until midweek. It will be my first snow ride.

All this snow, work is gonna tire me out tonight... and football Sunday... Big weekend.

Just got done snowing here, got a little over a foot, but the forcast is for one to three today with up to 40mph winds. Can you say drifts:)
What an idiot I am... here is why you should never take shortcuts:

Turns out, I hit this stick about 100 yrds from my house that punctured my lower radiator hose and all the fluid drained so quickly that the overflow resevoir still showed a full level. Then when I parked the quad in the garage, there was no fluid left to leak out so I never realized I had a leak!!! I followed all the diagnostics, but instead of taking the hood off and checking the radiator I assumed there was coolant because of the overflow resevoir.. DOH! The reason the thermo switch didnt turn the fan on is that it was not immersed in any coolant... Then 4 weeks later trying to get the stupid part and I dont need it after all!!! Now I have to wait one more week for the lower radiator hose... man I feel dumb! Shortcuts wasted a month of riding!

same thing happened to me but i went straight to the coolent level after reading this
I'm glad I saved someone else the frustration! haha

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