98 Ram heating problem. won't cycle
 

I have a 1998 Dodge Ram 1500 that I have had for about 9 months now... never had a problem with it until I went to work last Sunday morning.

I started it up on a very cold morning and let it run for about 10 minutes before cranking the heat on. When I went to cycle the blower switch from directing the heat from the windshield to the cab, the heat would not redirect to the cab.

I tried to cycle the heat to the floor also, and it would not move from the windshield at all.

Any ideas of where I should start looking to fix this issue? The heat blows strong and hot, it just won't cycle through anything?