The resistor is under the passenger dash just left of the blower motor
Short of it is the resistor controls the fan speeds for the blower. Easy to replace and to my knowledge only available through a dealer.
Mounted right in the AC/heater box under the hood.
You will have a bad blower resister and the part will be around $124.80 dollars.........
behind the glove box
Work you way from the blower motor first by checking that it has both power and ground and then check the rest of the electrical system............
99 Durango doesn't have a Heater Control Valve, It only has a thermostat
A Dodge Durango does not have a water control valve in the heater plumbing. The cabin temperature is controlled with airflow control doors.
How to replace the inside Spectra Heater Core on a 2000 dodge durango??
This website might be helpful.www.dodgeparts.com/
Start out by checking the a/c blower and the blower resister.......
No such part exists