Heater/Defroster question

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challengergary

challengergary

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Heater/Defroster question
Okay - It's f'n FREEZING and we've got this lovely light freezing rain going on here. Great time to discover my "new" Duster's heat & defroster is not working. :angry7:

I know it is just a matter of getting the air to flow over the heater core but how do I do that if the controls do not seem to be working? My blower motor is blowing and the heater hoses are running into the firewall but the air is just plain old cold air that is blowing. The heater valve under the hood is MIA but that just means I am getting full flow through the core regardless of the temp setting, right? Sooooo, how do I keep from freezing my nuggets off???


HELP!!!
 
Are both heater hoses hot or just 1?

If just one is hot, either the heater core or the return hose might be plugged, not allowing any water to flow.
Also, the temperature cable from the dash to the heater might not be working.
 
I bet it's the heater core - I've had to replace it in every old Mopar I've had. Kinda a PITA - you gotta pull the whole heater box out to put the new one in.
 
like said above check the heater core to make sure it is not plugged first. second you need to locate the blend door and see if it is switching between hot and cold air. the door is usually cable operated and it sits right next to the heater core. if the cable is missing or broken you can either fix that or move the lever by hand to get it to work till you can fix it.
 
What I'd suggest is to back flush the heater core. That means to take both heater hoses off at the engine, pour water in one hose and blow compressed air into that hose in the opposite direction of normal flow. Just have the other hose in a gallon jug to catch the crud that may come out. Keep flushing until water comes out clean. May save you from buying a new core. Has worked for me many times.
 
I drape both heater hoses over the fender and use a garden hose to flush in both directions until the water runs clear. The cable on the very bottom of the heater controller operates the blend door (___WARMER____>.
Look under the dash with a flash light and see if moving the lever is moving a door. They often get debrie trapped in the case blocking the door movement, then operater forces the lever and breaks the plastic pin in the controller. We can fix it when you find the problem . Good luck :)
 
If the Duster had factory air, the blend air door is controlled by a vacuum dashpot (push-pull device). There should be two vacuum hoses coming out of the firewall high on the passenger side. One goes to the heater control valve, the other to manifold vacuum. The manifold vacuum hose goes from the engine to a selector valve controlled by a lever on 73 & +, the selector is pushbutton operated on 72 & -. The postions are Max A/C (recirc), A/C (fresh), vent, heat, and defrost (compressor does not run). If this vacuum line is MIA, nothing works. Two of the positions are for A/C and have electrical contacts (for the compressor) so you may see sparks when you monkey around under the dash.

Forgot: There is a second electrical lead into the selector, either lever or pb. That lead is for the light bulb that illuminates the control.
 
Thanks everyone. I forgot to mention, the car did have factory air. The compressor and other underhood stuff is missing. I'll try everyone's suggestions.
 
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