The Fans Are Supose To Be On On Slow Speed With Aircon Switched On All The Time. If You Switch The Aircon On And The Cooling Fans Go On Fast Then Go Off Then Come Back On A Bit Like There Pulsing The Slow Speed On The Cooling Fans Have Burnt Out. Also Check The 40amp Strip Fuse On The Battery Fuse Box Check For Signs Off Fatigue To The Fuse As When The Fans Go Straight On To Fast Speed It Pulls Nearly 60amps And The Fuse Will Blow In The End