It could be a number of things. Two most common are a clogged heater core and bad thermostat. If you drive on the highway for awhile and you end up with some heat than it's probably the thermostat.
rear heating no working
Could be that the thermostat is stuck open, new thermostat fixed my 2001 Dodge 3500. If your temperature gauge is not reading warm enough, could be the thermostat.
Clogged Heater core... common problem with 2002 dodge
This may be caused by the ignition switch.
It's on the frame on the right side of the motor near the radiator.
heater core
195 deg f195 deg f
If it has rear heat it has two heater cores. One in the front and one in the back.
A blown radiator hose could not cause a 2000 Dodge Durango to not have spark and not start unless the heat damaged the computer in the vehicle. Sometimes when an engine overheats, the computer that controls the firing can be damaged.
The Dodge Durango uses a standard size automotive battery, but there are other options you may want. Some batteries offer more cold-cranking amps while other batteries are designed to work better in extreme heat.
Well I have a 2000 dodge durango and I had the same problem. I didn't know the answer so I kept using the a/c which the car overheated and cracked my radiator. Come to find out the fan for the a/c does not work! I guess there is a radiator fan and a a/c fan. Hope that helps!
Check your coolant level, If low you need to find the leak.