My temp light just went on for no reason (that I can see). And now even when the machine is cold it is on right from the start and does not go away. Does anyone have any idea what might me going on?

 

I would say your temperature sensor has failed in the closed positon, giving you the light, or it's range has gone to a small value. I would change that first.

 

I would disconnect the wires to the sensor first and check to see if you still have the light. A shorted wire to ground will cause the light to come on too. The sensor cost money, chasing a grounded wire cost you a little time to find it or just install a new wire around the short(easiest).

 

The 400 has 2 temperature switches. One is an oil temperature light switch and the other is a fan temperature switch. I am not sure if the light will come on if the fan switch is bad but it makes sense it woulf came on if the oil temperature light switch was bad.

The oil temperature light switch has a part number of (3530-037) and is about $70. There is a procedure for testing it in the manual.

 

Thanks for the confirmation. I spoke with my dealer and he said the same things. The machine is still under warranty so hopefully it wont cost me anything.

 

This site might help you.
http://www.alpha-sports.com/arctic_cat_atv_parts.htm

 

I had the same problem with my 03 400i a while ago, the dealer replaced the temp switch. I can't remember which one but as stated before, there are 2 of them. My temp light stayed on when I went riding and the fan did not come on, so I stopped riding untill it cooled down then rode it to the truck. After I got home and the bike was cool, I started it up and let it run for 5 min and the light came on again with no fan so I just took it back to the dealer! Maybe the 03 400's have bad sensors! Good luck, so far it is the only problem that I have had with my bike!