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Overheating 450

6949 Views 15 Replies 6 Participants Last post by  Juneau Rhino
I have a 450 with overheat light coming on. Here is what is going on.

Light comes on - fan doesn't run..

Pulled plug on radiator - jumper wire on plug and fan runs.

Replaced thermo switch on radiator - fan doesn't come on.

Removed the pack in the battery box and replaced with a 20 amp inline fuse. Started engine - light came on - no fan.

Installed a manual switch with relay. tapped into the blue wire going to fan. started Rhino, it heated up and light came on. Flipped switch, fan came on, cooled down and light went out.

Help !!!!!!!! I don't understand why the fan won't come on by itself.
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i was going to sy bad thermo but you already replaced that....

all your doing with the override switch is moving the thermo switch from the rad to your dash, so it should work both ways.
All I've done is put in a switch.

You're right - Should work but don't.
so you replaced the switch on the radiator?
Replaced thermo switch on radiator - fan doesn't come on.

if all you are doing is by-passing the switch in the radiator and the fan works then you have two bad switches. put a ohm meter on a switch that is not in the radiator it will read open, then with the meter still attached put it in a pan of water on your stove and boil the water the switch should close if it is good a bad one will not close or will close at the wrong temp
Pulled plug on radiator - jumper wire on plug and fan runs.

Help !!!!!!!! I don't understand why the fan won't come on by itself.[/QUOTE]
There is a possibility that the new switch has failed.
Other than that the only thing I can think of is there is a bad wire between the thermo switch on the rad and the fan.
I have digital dash. When the temp. light is on and I pull the plug on the sender in the head, it stays on. Is this normal for a digital dash?

Couple questions. Will an aftermarket sending unit thread into the head so I can install a temp gauge? If I install a temp gauge, will I have to somehow disable the temp light in the digital dash to keep it from coming on all the time.

Later tonight, I will be bringing it up to temperature and using the digital temp. gun.
The Laser Temperature Gun showed 155 degrees at the head.

Put a sending unit for a temperature gauge in the head where the idiot light sender was located.

Since I installed a proper gauge. I grounded the wire that went to the sending unit to the black. Light on the dash went out.

Fan cycled on and off but temperature never got high enough for it to stay on.

Don't have a place around here to ride it and give it a good workout.

Now if I can get the fuel gauge to work right.
ok so it was a bad connection on your light.

yes i have a water gauge sender in the head where the idiot light is.
Yea, bad sending unit. Just as well, I trust gauges a whole lot more.

Temp gun is a nice tool to have. Really helped solve my problem.
yup that was one o the first things I mentioned :)

glad it was something small, and yes gauges are MUCH better!
Is the fan kicking on by itself now? I put a gauge and over-ride switch on mine as well...Still need the fan to come on automatic, so as to eliminate the human error part of overheating....especially if someone else rides your ride!!
Yes, the fan is cycling on it's own.
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