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Cooling fan question

15K views 9 replies 6 participants last post by  doorfx 
#1 ·
Working on a 2002 Arctic cat 500 4x4 for a friend, he asked me (while I'm at it) to check out why his fan doesn't work. He currently has it wired direct and turns it on with a switch (and works this way), but he sometimes forgets to turn it on.

My question is, under normal circumstances does the fan come on when the key is turned on?

Should it run constantly or does a temp sensor (or something else) trigger it to go on and off?

I appreciate all help. It's much easier to fix a problem if you understand how the system is supposed to works!
 
#2 ·
<div class='quotetop'>QUOTE (skynyrdcat @ Mar 26 2009, 09:16 PM) <{POST_SNAPBACK}></div>
Working on a 2002 Arctic cat 500 4x4 for a friend, he asked me (while I'm at it) to check out why his fan doesn't work. He currently has it wired direct and turns it on with a switch (and works this way), but he sometimes forgets to turn it on.

My question is, under normal circumstances does the fan come on when the key is turned on?

Should it run constantly or does a temp sensor (or something else) trigger it to go on and off?

I appreciate all help. It's much easier to fix a problem if you understand how the system is supposed to works![/b]
Mine comes on with the turning of the key, but only if the temp is high.
 
#3 ·
There should be a thermostat on the lower radiator tank which controls the fan. The thermostat controls the fan circuit directly without a relay. The thermostat should close (turn ON) when the coolant temp reaches 150-155*F and open (turn OFF) when the temp falls to 145-149*F.
 
#4 ·
I saw that (thermostst) in a parts diagram, but on the actual 4-wheeler it's not there (just an empty socket near the bottom left corner of the radiator where it looks like it should be). I assumed I may have looked at the wrong diagram and that it may not (thermostat) be standard equipment. The socket looks clean and smooth (not like it's been tampered with or anything) but no thermostat.

Is their any reason you can think of that it would have been removed?

Their is also a 1 wire sensor just below the carb (on the left side) that ties into the samew wiring harness, can you tell me what that one is?
 
#5 ·
<div class='quotetop'>QUOTE (skynyrdcat @ Mar 27 2009, 07:08 AM) <{POST_SNAPBACK}></div>
I saw that (thermostst) in a parts diagram, but on the actual 4-wheeler it's not there (just an empty socket near the bottom left corner of the radiator where it looks like it should be). I assumed I may have looked at the wrong diagram and that it may not (thermostat) be standard equipment. The socket looks clean and smooth (not like it's been tampered with or anything) but no thermostat.

Is their any reason you can think of that it would have been removed?[/b]
Maybe it failed and wouldn't allow the fan to run? I dunno Is there a splice in the positive side of the fan circuit between the fan and two-wire fan to harness connector?

<div class='quotetop'>QUOTE </div>
Their is also a 1 wire sensor just below the carb (on the left side) that ties into the samew wiring harness, can you tell me what that one is?[/b]
The only single wire sensor showing is the water temperature sensor. The sensor should read open circuit to ground at cold/normal temps and short circuit to ground on over heat.
 
#6 ·
I am having this exact problem I was told that it doesn't come on very often I finally rode it without the fan coming on until the overheat light came on then we shut it down. I don't see the connections that show in the service manual to the thermostat on the rad. There is supposed to be a diode that goes into the rear of the motor somewhere I need to take a closer look tho.

My Plan:

inline temp gauge
custom gauge pod
switch

I had mine on a switch then "fixed" it so it wouldnt need it tested it by grounding it and it worked its just not triggering to come on. If I figure it out I will let you know otherwise I would consider what I'm doing.

The fan comes on at 88-93 C(190-200F)
and shuts off at 81 C(177F)
pretty sure overheat light comes on at 210-220
mark the gauge and be on your way

Joe
2001 Arctic Cat 500 4x4 Custom Green Manual(Clutchless)
Upgraded 19A Battery
Custom Cut Air box
K&N Air Filter(Custom Large Air filter made for a Honda racing machine)
K&N Chrome Oil Filter
Custom Fuel filter(Doesn't come with one)
3/8 aircraft aluminum rear diff skidplate
steel hand brush guards
studded tires 25x10x12 Kenda bearclaws(Missing a few now upgrading soon)
New Front End Bearings, rebuilt front diff with all balls racing bearings, rebuilt winch, recovered seat, new tie-rod ends, new front end bushings, ground and rust painted frame and racks, new headlights, new brake pads, new foot shifter, New starter relay, new reverse cable, new steering bearings
Soon to Come:Handle bars, Tires, Muffler, full length skid plate, 2nd rear winch(just needs to be installed), more custom stuff
 
#8 ·
Please don't hijack threads especially really old ones. If you have a question start a new thread in the appropriate atv forum :)
 
#10 ·
 
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