Blower motor resistor assembly is located under dash board on passenger side.
For the 1989 Dodge Ram, the heater blower motor resistor can be found on the passenger's side, on the bottom of the heater box. It is beside the blower motor.
Most likely a failed blower resistor.
Diagram for location of blower motor resistor can be found herehttp://autorepair.about.com/library/images/bl441a-lib.htm
4x4 fuse location on a 97 dodge pickup
On the firewall pass side.
A 1994 Dodge Ram does not have a ballast resistor.
No such part on a 1997 Ram.
Replace heater motor resistor.
No such part on a 1997 Cummins.
1997 dodge ram 1500 2wd 1500 engine block heater location
The Blower resistor should be tested which is located near the blower motor, the resistor is probably faulty.
Look behind master cylinder, it will be white.