71 A/C Heater Box

Technical Question and Answer - On topic to 71-74 Plymouth B-bodies only.

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Tulzscha
Satellite Coupe (RL)
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Joined: Sat May 28, 2016 6:37 pm
My Cars: 71 Road Runner 383 Auto

71 A/C Heater Box

Post by Tulzscha » Sat May 28, 2016 6:50 pm

Trying to finally get my heater controls to work after a few years. I have looked at a few forum posts on which vacuum lines connect to the actuators, and it has helped alot. The only problem is that air constantly blows from the vent no matter what position the selector switch is set to. I have noticed the door controlled by the A/C actuator only moves part way and then hits the heater core. Is that door supposed to completely close off the vent duct and blow more air into the heat/defrost area?

71_bronze_gtx
GTX (RS)
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72 cuda repli-mod
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Re: 71 A/C Heater Box

Post by 71_bronze_gtx » Mon May 30, 2016 9:38 pm

As I read the service manual, if your controls have a "vent" position, you have "stratoventilation", which appears to be an option separate from A/C. Without A/C, it is definitely an option.

Stratoventilation has an actuator to route un-heated and un-cooled air to the dash registers. It sounds like your actuator is stuck open, or not able to completely close. Could be the control, or could be the actuator. I'm attaching an excerpt from the FSM as a picture.
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strato.jpg

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road chicken
GTX (RS)
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Re: 71 A/C Heater Box

Post by road chicken » Wed Jun 15, 2016 11:18 pm

MIght be something jammed in the box too. Check and see if you have a full swing. Maybe a piece of foam or rhe gasket is stuck in the way.
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