99 Durango doesn't have a Heater Control Valve, It only has a thermostat
How to replace the inside Spectra Heater Core on a 2000 dodge durango??
Its a Durango.......not a Drango.
Usually just heater hoses-part of you cooling system which you can bypass if you have to and can't afford to fix
It is inside the HCAV housing under the dash.
Your heater core is leaking you probably also noticed the heater may not be working as well.
pull the dash
Typically this is the heater core bypass tube. Takes warmer block coolant to heater core for faster cabin warm up.
Drain the water from your Dodge Ram truck cooling system. Remove the water lines from the heater core. Remove the heater core retaining bolts. Reverse the process to install the new heater core.
The temperature blend door may be at fault.
Your heater core is plugged up....check the two smaller water hoses that come off your water pump. if one is hot to the touch,and one is noticably cooler to the touch, then theres your problem....and it is an absolute bear to change. Go to Google Search and type Back flush heater core 2000 dodge durango. Follow the directions you will find there. It's not that difficult to do.
the hole dash has to come out . just change mine in a 02 dodge ram 1500.