wondering if i could get some ideas on what to look for? i have replaced my heater valve. i have looked for cracked vacuum hose's and every thing seems to look okay. i pulled out hvac switches and radio to looked behind them, every thing is working. moved the cold to hot switch which moves this rod thing in and out(what does this rod due when moves in and out of what looks to go twords the heater core?). when moving the top lever from a/c to heat or vent that seems to work as well air, comes out through the correct places.(vents when a/c. floor when heater and when in max a/c this flap opens behind the glove box). both hoses going to heater core get warm after car is running. i looked on past threads and tried every thing i could find. dont know if matters but a/c does not work either will do that next figure its freon or something
heater not working?
- Thread starter AV62NV
- Start date
turbobob924
Member
- Joined
- May 28, 2001
the hot/cold is controlled by vacuum. there are 2 skinny hard vacuum lines that go into the passenger compartment and connect to the control unit. One of mine got disconnected and I have the same problem. I am still trying to trace the thing. It goes behind the passenger inner fender by the antenna. Hard to get at without removing part of the fender and inner fender well piece.
You CANNOT get to that vacuum connection by removing the outer fender.
You can get at the Heater vac connection from inside the car. Remove the underdash panel. You may have to remove the ECM for a little more access. The vacuum block is up at the upper right hand side. Pull it out to and you can reattach the plastic lines
You can get at the Heater vac connection from inside the car. Remove the underdash panel. You may have to remove the ECM for a little more access. The vacuum block is up at the upper right hand side. Pull it out to and you can reattach the plastic lines
i checked every thing and still no heat. now i have replaced my heater core(read that it could be stopped up)and still nothing. does any one have or could tell me where to find a diagram of how the vacuum system works for the hvac. i am not getting a vacuum to the heater valve and don't under stand why? i know the vacuum works for every thing else all the flapper doors open/close and air comes out of the correct places.
ELLISDALLASWE4
Member
- Joined
- Nov 7, 2005
Get someone to start the car, put the AC on VENT now while you are looking at the new valve get someone to move the temp control from hot to cold and back ...SEE if the the new heater valve rod moves. If it doesn't you have a vacuum leak ... check all the lines...there is a chart on top of the AC unit on pass side... If it does move then take all the stuff out of the glovebox while it is open close it about 1/4 inch now push in on the left side of the glovebox and let the glovebox door open all the way down.... Look in the opening towards the upper left side you will see a cable that should be anchored with a clip ..... this opens and closes the hot or cold rod..... this clip is probably broken... If so that is the problem.... it can be fixed by drilling 2 hole and using 2 zip ties to hold the cable...Let us know what you find
DailyDrifter
The Slow and the Curious
- Joined
- Dec 5, 2007
Put a vacuum pump on the heater valve, and see if you can manually get heat.
bagged84regal
Member
- Joined
- Dec 2, 2007
I had this same problem and it was a vacumme you only have to find it and figure out where its leaking, there are tons of them in there anyway.
i have now come to understand a little more of how the vacuum works.i know you guys say i have a vacuum leak, which could be tons of lines. there is only one line that goes to the heater, valve which is the gray one( from the back of hvac control all the way to heater valve). i disconnected the line from hvac and from the heater valve, plugged one end with a golf pin and no air would flow through, unplugged it and air would flow through. i cant figure out why no vacuum to my heater valve. . from taking out and replacing heater core to taking stereo out and completely taking out and apart the hvac control to see if broken. seems the only line that vacuums to the hvac is the pink line, which is the same line that hooks to the check valve next to the driver side valve cover, that line feeds the hvac system. i guess now i will try to replace the hvac control see if this solves. if you have any thoughts please would love the help.
Not exactly. The A/C outlet controls are vacum operated. You need vac to switch from blowing out the heater to the A/C vents. Sounds like that is happening.
The Blend air door is cable operated. There's a cable from the control to a bellcrank on the heater box. (you can get to it from the glovebox.) That belcrank is plastic and breaks easily. The rod going through the firewall also has a plastic end on it. If the belcrank moves check the arm see if it's still attached.
all the a/c vents and heater vents work. the whole hvac system seems to get vacuum, it just wont vacuum the heater valve. i checked that line by plugging it like i stated above( the grey one behind the glove box, which goes to the heater valve). i guess i could try with smoke. the whole blend air door works all cables attached i checked the door when i replaced the heater core the other day.
