Cold air exiting under steering column when heat is on, why
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From: Sanford, NC
Cold air exiting under steering column when heat is on, why
I'm curious if the following is normal, although I can't imagine that it is...
When I have the climate control fully automatic, and the heat set high enough to deliver hot air, I will have cold air lightly blowing from the gap under the steering column between it and the knee bolster. So even though the system is delivering hot air at the floor or out the panel vents, cool air lightly blows on my knees and is quite cold.
This cold air only blows out of this gap at highway speed, and if I set the heat to near maximum (80+ F) then the cold air is stopped. If I am just driving around in town the cold air doesn't seep in. So it seems tied to speed, and perhaps some damper/flap setting.
So unless is normal for the system to mix cold air and blow it out under the steering column, this seems abnormal. It is?
If abnormal, any idea what damper/flap may be malfunctioning or other ideas how the cold air is being pushed in?
And just to re-confirm, I am getting full heat from the system so the circulation pump is fine.
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When I have the climate control fully automatic, and the heat set high enough to deliver hot air, I will have cold air lightly blowing from the gap under the steering column between it and the knee bolster. So even though the system is delivering hot air at the floor or out the panel vents, cool air lightly blows on my knees and is quite cold.
This cold air only blows out of this gap at highway speed, and if I set the heat to near maximum (80+ F) then the cold air is stopped. If I am just driving around in town the cold air doesn't seep in. So it seems tied to speed, and perhaps some damper/flap setting.
So unless is normal for the system to mix cold air and blow it out under the steering column, this seems abnormal. It is?
If abnormal, any idea what damper/flap may be malfunctioning or other ideas how the cold air is being pushed in?
And just to re-confirm, I am getting full heat from the system so the circulation pump is fine.
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Mine performs the exact same way, Al.....with the exception that I get it at slow-speed/idle as well, but at reduced flow-rate. As best I recall, manually setting the mode doesn't defeat it, either. In the summer, I don't notice a flow path there, either hot nor cold.
It sure seems a big mistake in climate-control design, which DOES happen from time-to-time. If a flap actuator is failing, it should flag a code on the self-test, I should think.
It sure seems a big mistake in climate-control design, which DOES happen from time-to-time. If a flap actuator is failing, it should flag a code on the self-test, I should think.
Thread Starter
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Veteran Member
Joined: Mar 2014
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From: Sanford, NC
Mine performs the exact same way, Al.....with the exception that I get it at slow-speed/idle as well, but at reduced flow-rate. As best I recall, manually setting the mode doesn't defeat it, either. In the summer, I don't notice a flow path there, either hot nor cold.
It sure seems a big mistake in climate-control design, which DOES happen from time-to-time. If a flap actuator is failing, it should flag a code on the self-test, I should think.
It sure seems a big mistake in climate-control design, which DOES happen from time-to-time. If a flap actuator is failing, it should flag a code on the self-test, I should think.
Ah, well good to know I don't have something else to add to my fix-it list
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Meant to update: the other morning after posting, I took care to observe, mine also dissipates at slow speed and ceases when I come to a stop. I cycled thru all manual distribution modes and it had no effect.
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Joined: Aug 2012
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From: Chesterfield, Derbyshire
This sounds to me that cold air is entering at speed, and it could be that you only notice it when temperatures are cool outside.
Al; I think you were on the right track when you thought about a flap setting. Are there any vents or seals in the area that are not doing their job?
Al; I think you were on the right track when you thought about a flap setting. Are there any vents or seals in the area that are not doing their job?
Kevin,
It has to do with heating....believe me, if it did this in DFW in August, I'd surely notice!
My first thought was that a firewall grommet had rotted or fallen out. Inspection revealed no such problem.
Now, I am convinced it is air from the HVAC that has somehow bypassed the heater core. My hunch is that it is post-evap core air, as it would be very prominent in summer if it were ambient. Could well be a foam flap-seal or some such thing has given up. Set-point significantly above cabin-temp makes it stop, but no amount of fettling with the manual distribution modes does, so I have to conclude it is a designed-in bleed, though for the life of me, I can't IMAGINE what they were thinking.
It has to do with heating....believe me, if it did this in DFW in August, I'd surely notice!
My first thought was that a firewall grommet had rotted or fallen out. Inspection revealed no such problem.
Now, I am convinced it is air from the HVAC that has somehow bypassed the heater core. My hunch is that it is post-evap core air, as it would be very prominent in summer if it were ambient. Could well be a foam flap-seal or some such thing has given up. Set-point significantly above cabin-temp makes it stop, but no amount of fettling with the manual distribution modes does, so I have to conclude it is a designed-in bleed, though for the life of me, I can't IMAGINE what they were thinking.