07 brute force belt light stay on
First of all, your belt MAY need replaced, depending on how many miles/hours you have on it. But if your belt is not the issue, You may have just tripped the 'belt light switch', which is located in the transmission housing. There is a way to reset the light, as I'll explain, but if it comes back on right away after you start riding again, you will probably need to replace the belt so you do not damage your transmission.
Ok, now, to reset that light---
Get yourself a piece of electrical wire, like 20 or 22awg, about 12" long will do fine. Get a set of small alligator clips and put the alligator clips on both ends of the wire to make a 'jumper'.
Next, take your seat off of your ATV. You will notice, toward the back of that compartment, just in front of your little tool pouch holder, there is a wiring harness. Disconnect that wiring harness. Flip the female end up towards you and you will see 4 little connection pins sticking out. Take your alligator clips and hook the clips to the 2 bottom pins in that half of the connector.
Next, turn the key on.
Now, on the right side of the ATV by where you put your foot, you will see the engine brake actuator mounted to the side housing of the transmission case. There will be a wiring harness coming from the actuator. The wiring harness splits into 2 different sets of wiring harnesses. Find the smaller one of the 2, (it will be the one that goes up into the box on top of the housing--that box is the switch) and disconnect it. Let the belt light flash for about 5-10 seconds.
Next, just turn the key off.
Plug the belt switch harness back together, remove the jumper from the back harness and plug that harness back together. You should hear the actuator run for about 5 seconds (it is resetting the engine brake system). Put the seat back on. Start it up and try it out. Have fun!!