Bedroom Furnace

[Waynesplace]

I have a 38" Holiday Rambler with dual furnaces. When I turn on the front furnace you can feel the force of the air when you but your hand in front of a heat register. When I turn on the back furnace there is very little flow coming from any of the registers to this furnace. Any ideas on what might be the issue or how to go about diagnosing what might be up?

[67fisher]

It is unlikely that a portion of the ducting has fallen and is blocking the airflow so I would look at the furnace itself to see if the area surrounding the blower wheel is clear.

[Waynesplace]

How do I locate the blower motor for the rear furnace?