heater blowing constantly hot even when not on.

heater blowing constantly hot even when not on.

Postby tommy50 [OP] » July 15th 2013, 4:40pm

the car is always warm. if I turn the heater controls right down to cold it still comes out hot. even when my heater switch is off the air comes through hot. any help please.
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Re: heater blowing constantly hot even when not on.

Postby chevymaher » July 15th 2013, 6:58pm

Fine can of worms you've got yourself into here.
There a door inside the heater control box way way under everything know to man in the dash. It closes and blocks the heater core when heat is off. One of 2 things happened. The vacuum diaphram went bad, not very bloody likely. Or the vacuum to it got broken under the dash. Again not very likely.

Or the water from the air conditioner drain is partially blocked. Water from condensation is in there. Hair dirt and lint made a nice little silly putty material and it holding the door from closing.

Easiest solution to try is the Infamous Lumpy water ball check valve in the heater hose under the hood. And just turn the hot water off in the summer months.
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Re: heater blowing constantly hot even when not on.

Postby redfury » July 15th 2013, 11:10pm

Now, if you have vacuum operated controls for the heat, and on the 95.....I'm not sure as that year they started changing over to the new style...there is a valve on the heater hoses down by the alternator. If you have a vacuum connection that comes out of the firewall with two sets of hose connections on it, the lower connection controls the heater valve. Normally, the heater valve is supposed to be open all the time...that way you will always have heat. When the dash controls are set to cool, the controls send a vacuum to the valve and it closes. You can see the valve open and close as it works just like the vacuum pots under the dash that control the blend doors.
A temporary fix usually becomes a permanent solution, therefore it does not exist.
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