Dodge: dodge neon defrost, technical service bulletins, vacuum leak

Question
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Followup To
Question -
When i put my 2000 neon on defrost i get very little heat.on other settings i get good heat(with it on recirculat air)in floor position.
i have already change thermostat with no luck
antifreeze is full (no leaks),it seems like from the rt side of dash heat comes out & cold from the lt
i am baffeled please help
i think there may be a cold air vent open somewhere?


Answer -
It sounds like a vacuum leak,can you hear the dash window change settings when you turn the control?If not it is definitely a vacuum leak.

Follow up question-
is there any particular area to start looking for a leak?


Answer
There should be some small vacuum lines that run from the firewall to the intake over next to the side the heater core is located you'll probably have to add a check valve to fix the problem.To do this i would check the internet for the technical service bulletins for your make and model.