How do I turn it off????

[Pa Goose]

I can't take it anymore! The heater/AC control does not work so I have heat on constantly. In the winter it would be a good thing. I looked up behind the control and saw there are several vacuum hoses connected to the back of the multiport valve. With the temperatures in the upper nineties and heat index over one hundred, ad Not mad just cooking!!!

 

[Yoda]

John,

Here is a photo copy of the switch

Note the top left drawing.
On the opposite side of the vacuum hoses is the heat control lever. This lever fits into a Cam that has a diaphram that moves across grooves in the cam to control the vacuum switching of the temp by moving the temperature control cable...

What probably has happened is the lever (Switch Lever) was forced at sometime and has either jumped out of the track or has broken where it fits into the track.

I took my apart and fixed the lever, only to have it jump out of the cam after about a year and half ad Next I went in and made a small plastic washer to fit over the lever between the lever and the point where it attached to the cam. That took care of the problem

If you do take this switch out, I suggest you have an assy. manual handy and lots of patience... it is spring loaded and has to go back together right for the cam and the diaphram to function properly. I did it all from the passenger side with the seat out and with both side panels off the console.

Good Luck

Bud

 

[67HEAVEN]

A shut-off valve in the lower rad hose will cure the constant heating problem. Just re-open it in the fall.

Most auto supply places should have it.

On midyears, the bottom heater hose is 5/8" and runs from the intake to the lower heater connection.

Check your C3 with AC to get the correct hose and consider whether this is appropriate for your car with AC.

 

[vmrod]

Look up Bobchad's homepage. He has a very good and extensive list on remedying the problem.

 

[67HEAVEN]

Look up Bobchad's homepage. He has a very good and extensive list on remedying the problem.

Good idea. Bob's new forum name is his real name Bob Chadwick, and here's his excellent page on the problem.

http://home.comcast.net/~chadwick.robert/ventilation.htm

 

[Bob Chadwick]

I can't take it anymore! The heater/AC control does not work so I have heat on constantly. In the winter it would be a good thing. I looked up behind the control and saw there are several vacuum hoses connected to the back of the multiport valve. With the temperatures in the upper nineties and heat index over one hundred, ad Not mad just cooking!!!

There are actually two sets of controls here. One controls which duct the air comes out of. The other controls the temperature. The duct control can be a pain with vacuum and actuators to deal with. The temperature control is spring loaded wire that can be adjusted to control at what point the door that mixes the hot and cool air is closed letting only cool air in.

This does not always have the intended affect because the seals in the duct work are old and leak hot air. As Bob pointed out, a lot of people have replaced the vaccuum controlled hot water valve with a manual shut off. Ths prevents any hot water from entering the core. This works pretty well. However, I think you will find that unless you find all the sources where hot air can enter the ductwork, over the course of the driving you will notice the temperature of the air coming out of the duct to gradually creep up as air heated by the exhaust enters the system.

If you have a/c, there is also some thought that the proximity of the evaporator, or is it the condensor (I can never keep them straight), box to the exhaust manifolds transfers heat to the box and heats the temp of the air inside the system.

On a 70 - 75 degree day, my duct air will eventally come out at around 85 degrees. Fortunately I have a/c. I'm still working on sealing up sources of hot external air. The car is in the paint shop now, but when I get it back I'm going to get some gasket material and try and seal up the area where the heater hoses go up into the car as it is pretty open to heated air.

Let us know what you are doing and how it works out. You can never take too much heat out of this system.

 

[80convertible]

I had the same problem. I installed a manual brass shut-off valve to the inlet hose to the heater core. No more hot water circulating thru the heater core. Next I disconnected the brown wire at the blower motor connection in the engine bay. The blower motor is constantly on... there is no off position. By disconnecting the brown wire only (don't cut it, simply disconnect it) you disable the low speed switch selection thus creating an off position. You end up being able to turn off the blower motor as well as significantly reduce cabin heat by not allowing heated coolant to circulate.