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Topic: Heater Problem (Read 4564 times) previous topic - next topic

Heater Problem

When I change the heater output from "defrost" to "mix" to "floor" nothing changes. I thought maybe the heater just wasn't working and posted a thread about it. Today I played with it for a little while and it seems the setting don't change. I could swear they were changing the other day but I might be wrong.  What should I check? Is this a vacuum leak or some sort?

Heater Problem

Reply #1
hopefully someone else will chime in on this because my mustang only blows through the defrost vents and the floor. doesnt come out of the dash vents. maybe our problems are related
1971 Camaro Blown 640ci
1988 T-Top Mustang
1980 Mustang coupe
1988 Thunderbird TurboCoupe
And a purple mini van! :burnout:

Previous Thunderbirds:
1988 Sport

Heater Problem

Reply #2
Hmm, good questions, you may have vacuum leaks behind the dash, not allowing the doors to open for some settings.

Personally, I did the rotary  conversion and I have no idea what "mix" does, but it sure doesn't come out the front vents. I have to turn it to "vent" to get air out the front vents.

Come to think of it, that MAY be my problem, but the hell with taking that back apart, I'll wait.
1983 Tbird with '03 Split Port V6 motor swap done! Headers, dual exhaust, 500CFM Edelbrock, 3G upgrade, Electric fan. 3.73 Gears and an FRPP Limited Slip. Five lug complete! 5-Speed conversion complete! Standalone Fuel Injection in progress...

Heater Problem

Reply #3
Well my problem started after I replaced my heater core but the car still gets warm and as long as the defrost works im good because there is NO WAY im going to take the dash back out again! lol Its a lot warmer ride now then before.
1971 Camaro Blown 640ci
1988 T-Top Mustang
1980 Mustang coupe
1988 Thunderbird TurboCoupe
And a purple mini van! :burnout:

Previous Thunderbirds:
1988 Sport

Heater Problem

Reply #4
Sounds like a vac line...I had something similar happen a few years ago. I did have to pull the dash back though, but I left all wiring connected, as I only needed enough room to see the line..
'98 Explorer 5.0
'20 Malibu (I know, Chevy, but, 35MPG. Let's go brandon, eh)

Heater Problem

Reply #5
Oh . Mine started after the heater core was replaced too! And I know what line was disconnected. For the life of me I could not find anyplace for it to go. I sure hope I don't have to pull the dash out again.

Live Fast, I'lll look at it once I'm done cleaning the yard today. I'll get pictures of the line, and maybe the two of us can figure out where it goes.

Heater Problem

Reply #6
Mix means exactly what it says. It mixes the air between the defroster vents and the floor. The "vent" selection puts heat out the vents on the front of your dash, that selection is not under the "heat options" but it puts out hot air.
...and there was light!

Heater Problem

Reply #7
Quote from: jpc647;303250
Oh . Mine started after the heater core was replaced too! And I know what line was disconnected. For the life of me I could not find anyplace for it to go. I sure hope I don't have to pull the dash out again.

Live Fast, I'lll look at it once I'm done cleaning the yard today. I'll get pictures of the line, and maybe the two of us can figure out where it goes.


Ok cool, Hopefully between the 2 of us we can figure it out. I must have pulled it a loose by accident because I tried to leave alot of the vac lines hooked up. I think I might have an idea of which one it is.
1971 Camaro Blown 640ci
1988 T-Top Mustang
1980 Mustang coupe
1988 Thunderbird TurboCoupe
And a purple mini van! :burnout:

Previous Thunderbirds:
1988 Sport

Heater Problem

Reply #8
Here you go.

Heater Problem

Reply #9
Thanks. I think I know which tube is disconnected. Its on the passenger side. It seems pretty short. I can't figure out where it goes. I'll get a picture, but I really can't understand the schematic enough to find it. I'll get a picture.






The only vacuum line I can find that not plugged is this one. It goes up the dash and then loops back down and connects to the unit with all of the little outlets in the first picture. The unit thats in the bottom left corner of the glove box.

It seems this line goes out to the firewall somewhere. The manual shows that it goes behind one of the support braces, but I can't find the nipple it connects to.

 

Heater Problem

Reply #10
Quote from: FordTruckFreeek;303247
Sounds like a vac line...I had something similar happen a few years ago. I did have to pull the dash back though, but I left all wiring connected, as I only needed enough room to see the line..


Can you elaborate a little bit? lol Is the line in the picture the one you had a problem with? Where did it connect to?

Heater Problem

Reply #11
Seems like a lot of you are having problems. I posted this in another thread. Luckily I had my dash apart reassembling it after painting the rusty dash frame. The vaccum actuator on the left controls the airflow between the defroster vents and the dash vents.

Heater Problem

Reply #12
Quote from: Live Fast;303240
hopefully someone else will chime in on this because my mustang only blows through the defrost vents and the floor. doesnt come out of the dash vents. maybe our problems are related


My Tbird is the same setup.. Check out the picture I posted. That is your culprit! With no vaccum to this actuator it defaults to airflow only to the defroster.

Heater Problem

Reply #13
Another pic with dash frame removed...

Heater Problem

Reply #14
What vacuum actuator? I don't see anything labeled that. I was under the impression the line needs to be plugged in somewhere above the cabin air recirculation thing.