Is the fan running? Our 6630 blew its fan motor quite early, under 3000 hours. It can be found under the drivers seat and has a couple of bolts that are positioned sh!tty, need a very long wrench (iirc 10mm one) to get to them (or just do as we did, get some plastic pipe and push the ring end into the pipe to get long handle).Our 6630 some days you can turn fan up to maximum speed and no air comes out of air vents set for upper body face,where as another day is fine,usual fan speed is 1/4 to 1/2
??The fan motor is perfect,just some days there is no air coming out of vents