So I had my son bring his 2014 foreman over for me to compare with mine. My 4wd went out when we tried to install a winch. So the 2014 when u turn the key switch on (not starting the 4 wheeler) and hit the 4wd button u hear a like engage noise in the "actuator"? Down near the drive shaft. But on the broken 2015 u turn switch on and hit 4wd button and no sound at all. Also I took the relay off the 2014 and tried it on tge broken bike 2015 and nothing. Then tried the 2015 relay on the good 2014 and the 4wd worked fine. So the relay is not the problem. Also when a volt meter is put on the orange wire (4wd wire) with key switch on it reads. When u hold the volt meter on the wire and hit 4wd button nothing happens in the meter but if u go another step and hit the differential lock button the voltage meter jumps or goes higher with its number. Does this help anyone with an idea of where I need to look next??? Cause I have no idea!!