W900L blower problem

[Skman]

I've got a 2013 w900 that has an intermittent blower motor problem. When I start the truck in the morning it'll be blowing air wherever I have it set. Then as I'm driving down the road... suddenly I'll have no air flow coming from the vent.
Sometimes it'll have a small amount of heat coming out (regardless of the fan speed setting). Sometimes there will be nothing coming out at all. Then as I'm driving...it'll just start working again.
Not sure if it's a faulty motor or maybe I should be looking for a wiring/resistor issue?
Thanks