[gburbage4]

Hi,

I have a '72 Le Mans with a heater that's always on (low) blowing hot air. That's okay in January, but not now. What are some things I should look at?

Thanks in advance!

George

[indymanjoe]

Even in the off position? I had a couple vacuum actuator's leaking vacuum and they wouldnt move the doors to shut off the airflow across the heater core.Do you have A/C?

[gburbage4]

Originally Posted by indymanjoe

Even in the off position? I had a couple vacuum actuator's leaking vacuum and they wouldnt move the doors to shut off the airflow across the heater core.Do you have A/C?

Indy,

Yes, even in the off position. I do have A/C.

I think I understand your explanation involving the leaking actuators, but would that also cause the fan to keep blowing?

I admit I'm not the most mechanically gifted guy; that's why I came to the experts!

Thanks!

[2002Z4CSS]

Sounds like the blend air door cable is disconnected or broken. Easy fix when you remove the glove box.

[gburbage4]

Originally Posted by 2002Z4CSS

Sounds like the blend air door cable is disconnected or broken. Easy fix when you remove the glove box.

From the "Ä Problem Well Stated Is Half-solved" file: I drove my car today and noticed that warm air only comes into the car while it's moving. If I'm stopped, nothing flows. It may be the door cable after all.

As for the flow-through ventilation, it must be a really low speed.


"...If I only had a brain."

[2002Z4CSS]

Originally Posted by gburbage4

From the "Ä Problem Well Stated Is Half-solved" file: I drove my car today and noticed that warm air only comes into the car while it's moving. If I'm stopped, nothing flows. It may be the door cable after all.

As for the flow-through ventilation, it must be a really low speed.


"...If I only had a brain."

Sounds like the blower motor is not working. The gravity is allowing the air flow while driving.

[gburbage4]

Originally Posted by 2002Z4CSS

Sounds like the blower motor is not working. The gravity is allowing the air flow while driving.

I should've added this happened yesterday with no climate control operating, except for open windows.

[PontGuy]

I completely re-worked the system in my 69 during restoration a few years ago and learned a bunch about it. Before the repairs I always got a bunch of heat coming into the car- not good when you live in Georgia.

The way that the 68-72 "flow through" A/C system is designed there is always an open path between the heater core and the car interior. The dampers control where the air goes and how much fresh/cooled air is blended in, but they do not isolate the heater core. Instead the system uses a vacuum-operated water cutoff valve to keep hot water from flowing through the heater core when the lower slider is in the far left (cool) position. A vacuum switch located behind the controller closes the valve. If the water cutoff valve is missing or not working then you will get heat in the car no matter what. You should see the valve mounted on the top front of the suitcase under the hood.

The fan speed position switch does not shut the fan off. But the main selector slider has a switch that cuts power to the system when in the "off" position (far left).

If everything is intact and working right, with both upper and lower sliders in the far left position the fan should not run and there should be no heat. So first thing to do is to try driving the car with the sliders set that way. If you get heat then the water cutoff valve is not closing.

In my case the water cutoff valve was bad, and water/antifreeze must have got sucked into the vacuum line because the vacuum switch behind the controller assembly was ruined. Sourcing up a new valve and a new vacuum switch was quite a challenge, but getting it working properly eliminated the heat in the car- except when I want it.

[indymanjoe]

The fan shouldnt be running in off.That has nothing to do with the actuators.Do all the fan speeds work correctly?

[gburbage4]

Originally Posted by indymanjoe

The fan shouldnt be running in off.That has nothing to do with the actuators.Do all the fan speeds work correctly?

Yes, they do. It seems as though when I actually kick in the heater, on low speed there's no change. I think that's a good thing!

[gburbage4]

Originally Posted by indymanjoe

The fan shouldnt be running in off.That has nothing to do with the actuators.Do all the fan speeds work correctly?

Yes, they do.

[tigergto]

Sounds like a bad switch. Don't see why the blend doors working properly or not would make a difference. When the switch is in the off position the fan should be off.

[gburbage4]

Originally Posted by tigergto

Sounds like a bad switch. Don't see why the blend doors working properly or not would make a difference. When the switch is in the off position the fan should be off.

Makes sense. Is this a hard fix?

I know if I have no choice, I have no choice, but as far as I can tell, my car's interior has never been touched. Attached is a pic of the car you're helping me with: Anaconda Gold with Covert Beige seats and doors, and Dark Saddle dash and package tray.

[tigergto]

Something dawned on me when I took My GTO for its first ride this year. The fan switch does not have an off position. Just low, med, and high.

[gburbage4]

Originally Posted by tigergto

Something dawned on me when I took My GTO for its first ride this year. The fan switch does not have an off position. Just low, med, and high.

That's true, but the function control switch on the top should turn off the blower, no? It did on my parents' '72 Le Mans.

[indymanjoe]

Your right lol

[gburbage4]

Originally Posted by indymanjoe

Your right lol

Since we're sharing dashboard photos, here's mine. The lighter is safely in the glove box so I can use a car charger.

[indymanjoe]

Sorry to get off topic,but the first time i plugged in my cell phone charger i think i heard my car moan in disgust lol

[gburbage4]

Ha! I thought mine would shoot sparks or something.

[tigergto]

From my 71 manual. HEATER CABLE ADJUSTMENT
1 Hold lever on top of heater case in full cold position. (full left or clockwise when viewed from above .)
2 Adjust cable turnbuckle so that the temperature control lever will drop into the detent for full OFF position".
Hope this helps.