Alright so i have been trying to figure out why the heat in my 96 cherokee isnt hot.I have flushed the heater core,tried replacing the heater control valve and it still wont get hot.I did notice though that the vacuum line that goes onto the heater valve has no vacuum to it.I disconnected the line from the vacuum canister and hooked it to the heater valve,which immediately opened,but the heat still didnt get any hotter with the valve working.I tried to find out where the little gray vacuum line goes,but it just enters the firewall.I figure the gray line goes to the heater core and has to attach to the valve since they work together.So i cant seem to figure out what is going on.Where does the line go? How do i get at it? Is the heater core bad? The thermostat? (runs at correct temp now though).Please help!

 

the gray gos into the back of the heater switch

 

i took the heater control out and tried tracing the line,but i think i just saw wires behind it(was one gray wire/line).When u switch the heater control u can hear a little woosh of air,so i am guessing its still connected???

 

btw the black vacuum line that goes into the firewall has vacuum,but the gray one coming out doesnt have vacuum.

 

you prob have air trapped in the heater core...it is the highest point in the system therefore air will get trapped there.

 

yeah either trapped air or maybe a thermostat have you checked that? it may be stuck open or rotted

 

the jeep runs at the correct temp,so i dont think it could b the thermostat could it?

 

when your jeep is running at norm temp and the heat is on, is your heater lines warm?