all the air is blowing through the defrost


Old 10-11-06, 07:29 AM
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Location: morristown
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Question all the air is blowing through the defrost

I have a 1996 Ford Ranger. It has a 2.3l engine 16 valve. My air conditioner, heater and vent air blows through the defrost no matter what setting I have it on. No matter if its cold air or hot. I need help diagnosising this problem please.
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Old 10-11-06, 08:58 AM
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I suspect that the control for the air mixture door device is not working, and that the door is stuck in one position. I would first look under the hood for vacuum lines leaving the engine to see if any are either disconnected, or are leaking. If the problem isn't found there, I'd lay down on the floorboard on the passenger side with a flashlight and see if I could see where the vacuum line connects to the air mixture door device, and/or see if I could move the door manually. I'd also do a search on automotive to see if there are any posts there related to this problem. One other thing to consider is a blown fuse. I'd inspect the fuses just to eliminate this as a possible cause.
Old 10-18-06, 03:55 PM
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Exclamation diagnosis complete and repaired

I had to ask the guys at One of their experts told me that it was a disconnected vaccum line. It defaults to defrost when one of these lines are unplugged. Thanks for all the advice anway.
Old 10-18-06, 07:12 PM
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That is correct check for a vacuum leak on the main hose to the A/C system. The hose that goes thru the firewall to the main control panel. It is on the right side of the firewall.
Old 10-18-06, 07:31 PM
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if the control panel is vacuum controlled then m,ake sure the vacuum hose is connected ot the engine and not broken or split or rotted out, you should be able ot trace it under the hood it should be coming out of the middle or pass side of the firewall somewhere, not very big of a hose

if its not vacuum controleld then its probably the control position switch, or it could be an actuator or door stuck in the box assembly

i would go with vacuum first though

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