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Go All Electric
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Discussion Starter · #1 ·
Cold here, and it will be for 3-5 more months. Need 100% heat function.

My heat is blowing hot air very well ... but through less vents as time goes on.

First, out of the two vents that are above the climate control assembly, the vent on the right started not letting the high frequency of air through ... as if it were clogged or something.

Today, the middle left vent was working perfectly but then it ramndomly stopped letting much frequency of air through .. just like the other vent.

I think that the passenger far side vent may be having the same problem, but I forget.

I know that the defrost/windshield vents, floor vents and my driver side far left vent, are letting air through well ... but these others seem to be malfunctioning.

I thought that it may have something to do with the Air Vent Mode Servo Motor ... or that there are simply just cracks and similar problems with the ducting. Am I right? Are there any other possibilities?

I need to fix this asap. I am going to try to get to my buddy's shop later today to see if they can give me a hand with it. Fast feedback is appreciated.

Does anyone know if the Air Vent Mode Servo Motor is vaccum controlled or electrical/mechanical/etc controlled?

Thanks for prompt/helpful responses. I want my heat through all my vents asap.

Best regards.
 
G

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I think the vents in the mk3's are all electric, because they work the same when the engine is off.

If you can HEAR the motor going, and have taken anything apart recently, you have have misaligned your vents, but with vent misc shutting off, my guess is either the blowers or you evironment control is on the fritz.

If you have a coolant smell, I'd check the heater core.
 

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Go All Electric
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1,183 Posts
Discussion Starter · #3 ·
No coolant smell.

I don't hear any motor ... but I do hear the air beeing blow as it should. Like I said, it comes through all vents except for the middle two over the climate control assembly and maybe the far right passenger vent.

I haven't taken anything apart in a long time.

Duct alignment was fine. This randomly failed. Maybe there are some cracks or other similar problems with some of the ducting leading to the vents that aren't letting air through.

It seems to be a high possibility that the Air Vent Mode Servo Motor is malfunctioning, but I do not know the exact mechanics/functions of that motor and I haven't messed with it yet.

Responses please.
 

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Go All Electric
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1,183 Posts
Discussion Starter · #4 · (Edited)
Update:

I'm not troubleshoot this evening because I have other things to do.

Please try to help as much as possible. If I have time, some times even when I don't have time :doh: , I speak up when I know something. Please give me the same courtesy. If anyone has experienced this or knows about it ... please explain your findings. Thanks.
 
G

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I've had that problem in an mk2, and some other older cars that I've owned. If you hear the motor, and stuff is just randomly not working, my guess is that whatever system controls flow/direction is broken. I dunno what its called. Check here for trouble shooting.

http://www.cygnusx1.net/supra/library/TSRM/ac/AC_15.html

I can't completly dianose your system, as its one of those things that so much could go wrong. Check your fuses if you get a sec too.

*edit* Try switching the vent direction on the control unit, see if it changes, and which ones work/don't work. This could mean bad connections in the wiring.
 

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Give Shawndude a shout... IIRC, there was a post 8+months ago on this very problem. The thread had pic's too of the location, etc...

I think it was Shawndude ???

HTH,
Patrick
 

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AWIDESUPIE said:
If anyone has experienced this or knows about it ... please explain your findings. Thanks.
I just checked mine to verify. With the sytem in the normal vent position (chest level), the airflow through all four vents is pretty even, but you can feel slight differences if you try.

If I switch it to foot & chest, the airflow through all of the chest level vents is obviously less, but the one on the right directly above the climate control is the weakest; probably putting out 25% less airflow than the others.

I can hear the motor/doors moving, but haven't taken it apart to see why the airflow in that one vent would be less.

Not much help here, Brian, but at least your problem may not be an isolated case - just worse than others.
 
G

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First, close off the passenger side vent. That should produce lot more flow out of the center one. The left side passenger vent, and the under the steering wheel vent are also connected into this. All of these influence each other.

If closing the other vents doesn't help, then I would check the flap operation. Keep in mind that changing the TEMPERATURE setting will change how the air flows out of the vents, even in a manual mode. The computer is always varying the hot/cold flap, and this in itself effects where the air comes out to some degree.

Anyway, to manually check the flap, remove the plastic cover under the steering wheel. There are about 5 screws, and 2 are hidden under the hood release lever.

Once you have that off, there is a big plastic pipe running under the steering wheel. Pull on it and it will come out. Using a flashlight, look inside the heater box through the big hole that leads to the pipe you just removed. You'll see how the flap is positioned, and if it moves correctly when changing settings.

If not, check the alignment procedure in the TSRM. The site is down right now so can't link to the adjustment section (it's at the end of the AC chapter).
 
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