Question with the heater.. Getting a little cold here.


C. Horel
Sep 8, 2003
On the back on the climate controll there is alot of different vacum lines or what looks like them. I was wondering if any of these were supposed to have pressure or vacum in them. Has anyone made a digram that shows what all those lines go to too. Im asking this cause my heater works but only blows out of the defroster even on the heater mode. And im trying to fix this problem. Or does anyone know what to do when a thing like this breaks like where would I go to get this thing fixed. Cause its like 28 degrees out and I freeze driving since it doesnt blow out of my vents.
In advance THANKS for all the help!
yah i get the heat. but not through the correct vents and also my high position for the heater will turn off if its switched to that
well if you wern't getting any heat then i could help you but as far as vacum and pressure lines i have no clue how that stuff works.
sorry i can't help but maybe another member here can help.

Try doing a search of the vacuum lines, use words like, yellow, purple, etc. which are the colors of the lines.

It has been posted before I believe.

Factory service manual has all that information in it. Well worth the $75 to save a bundle on repair costs. Helm Inc. has them for the 86-87 cars.

Purple line is the vacuum feed from the vacuum ball I belive. :)
If you're only getting heat out of the defroster vents, you have lost vacuum to the hvac system. With loss of vacuum, the doors are weighted so that you will have constant defrost.

If this is the case, start checking in the engine compartment for a vacuum hose that has come off and then work your way back to see if vacuum is present where the vacuum lines go into the passenger compartment on the passenger side of the engine compartment.
Nope the cruise doesnt work.

Also i will look for a vacum line that might come off or what not. thanks
Well the cruise and the vent control are on the same vacuum circuit so when you find the leak your cruise will probably work again too. Check on the drivers side of the intake behind the egr valve you will see two vacuum lines that go into sort of a black plastic box. This is where mine was leaking and caused the same symptoms you described. Check and make sure there is no leak here as it is easy for one of these to come out and its hard to see casually. One line goes into the egr valve and the other goe's a little ways and then splits into two directions. There should be 1 way restrictor valves in each of the lines that split off just a little ways down from where it splits. Little cone looking things. If your missing one of these it will probably also cause you a problem. Anyway like the other guys have said you have a vac leak somewhere.
alright i will check that out.. also i have another question, there are two black plastic lines that go hunder the heater box it looks like and i was wondering where those go to. or how do i get access to them to.