aa7kn

I need to know which line goes to what .
I have a 1991 jeep cherokee xj and I had some work done on the HVAC control and also replaced the heater core. but ever since it had the work done the heater just doesn't work correctly, I notice that when the control is not in the heat position the heater control valve in pulled in, and it is in the same position when I select the heat position. so I think the vacuume lines in the dash were connected wrong, or at least the heater line is. the A/C Normal/Max works so I know the vacuume input is working along with the max/norm position. I have been looking everywhere for information where the color lines go in the dash HVAC. I mean which one is the max/normal blend door , the heater valve, etc...if anyone has this info or knows a link on line where i can get this info. I sure would appreaciate it. I have uploaded a photo to better explain the color connections I am looking for.

thanks in advance

Fangio76

Those lines, except the black one which goes out the firewall and gets vacuum for all of them, go to blend door actuators. On my 1999 I remember the green one goes on the passenger side to either the recirculation blend door actuator or the hot/cold air blend door actuator. Yellow and blue go to a actuators on the driver side. I wanna say the yellow one is the one that controls whether it blows through the defrost or dash vents.
The Haynes manual has some good illustrations but I don't have it on me now.
Beside the video i linked below, look for videos of people taking apart the dash on your year model (ie changing heater core or evaporator etc) and you may be able to freeze the video at the right time of the disassembly and see if you can tell where they go.

Fangio76

This may help too

aa7kn

thanks for the fast reply. I understand the black line in the vacuum input to the switch. And all the other colors go to the verious vacuum motors. But really the one I need to know is, which one goes to the heater control valve out in the engine bay. I think mine is hooked up wrong because my heater control valve is always sucked in. It should release when you select the heater position but it doesn't. Any idea ? Thanks.