The swicth flashes back and forth about every second when I put it in to 4wd on a 05 750 burte force, and it don't seem to go in to 4wd.

 

You may want to check your atv tire pressure! I know this sounds daaaaa but if tires pressure is off 1 pound sometime wont lock N2 4wd. I f pressure okay than prolly wire or bad sensor to 4wd. or switch just have to check all wiring.

 

Wow!
Do you even own a same or similar quad that has the 4x4 system like the BF750?
There is no sensor to check or replace on that 4x4 system.


If the flashing is exactly 1 second apart (2-second cycle), that means the engine brake actuator is bad. When it is bad, it disables the 4WD engagement. Another way to confirm is to listen to the EB actuator homing sound when you shut off the ignition. If you don't hear it, then it is definitley bad.

 

Haha! How do it disable without an acturator. You are right brake acturator is prolly the problem!!! But what is an acturator? I understand an acturator and an sensor is an electonic devise that detects movement or incease in resistants or increase voltage, etc.I guessed i used the wrong term here! Just trying simplefly terms for the none atv's guys! Sorry for the confusion!

 

There is a (second) ECU that controls the both 4WD engagement system and the engine braking system. It is aka Control Unit on Kawi. The Controle Unit automatically disables the 4x4 engagement system if the correct voltage is not received from either 4WD actuator or the engine brake actuator - so there are 2 actuators. The actuator is a dc stepper motor that precisely turns only certain revolution per voltage input. In each actuator, there is a potentiometer that measures the rotational position of hte stepper motor and in terms of resistance and sends its position info (via voltage=current x resistance) to the Control Unit. That's how Control Unit knows whether the actuator is working or not, and it decides what to do. It was quite amusing when I read your suggestion telling the guy to check the tire pressure for this problem, to say the least.