weird vent behaviour

[525i winter driver]

can anyone pin this for me?

my center vents blow cool air all the time no matter where i set the centre wheel or the controls on the climate control panel. except on warm/hot starts when it blows warm air with a tiny tiny hint of coolant for about 10 seconds and then goes back to cool again.

the defrost and lower heat vents are always blowing warm/hot air and even when i set them closed there is a tiny bit of heat coming out.

all this no matter what i set the controls to... the fan just blows it softer or harder (errr...). i'm thinking i could have screwed something up when i installed my stereo and had the center vents out or when i took the 'sword' out to change the microfilter that i don't have. or maybe my heater valves got stuck over the winter. it used to work great i can't really say exactly when it happened it was over the winter and i always had the heat on.

help would be appreciated it's getting hot in here!

[shogun]

center vents always blow a mixture of fresh unregulated air and heated air, see here blue and red signs
http://bmwe32.masscom.net/johan/center_vents/air_distribution.jpg

[DaveVoorhis]

The thumbwheel controls a servo on the HVAC box. As I recall, the servo mount and/or linkage has a tendency to break. I've seen a Web site on repairing it, but at the moment I can't find it.

[525i winter driver]

center vents always blow a mixture of fresh unregulated air and heated air, see here blue and red signs
http://bmwe32.masscom.net/johan/center_vents/air_distribution.jpgthanks for that...
i used to be able to control it with the thumb wheel in the centre vent...
according to p33 in my manual... under "Stratified temperature pattern conducive to fatigue-free driving" (LOL!) , 'Air entering the outlets at the front doors and in the instrument panel can be varied by the thumb wheel... up: warmer, down: cooler'

this used to work, and i'm getting more heat through the top and bottom flaps than i did last summer even when they are completely closed. something's very different... i'm wondering about my auxiliary coolant pump now...

[525i winter driver]

The thumbwheel controls a servo on the HVAC box. As I recall, the servo mount and/or linkage has a tendency to break. I've seen a Web site on repairing it, but at the moment I can't find it.
thanks - i think the thumbwheel thing is more of a symptom than the actual problem tho... i'm really suspicious of the heater valve and aux pump setup oh well looks like i'll have to tear things apart some more...

[93 525 Paul]

The thumbwheel controls a servo on the HVAC box. As I recall, the servo mount and/or linkage has a tendency to break. I've seen a Web site on repairing it, but at the moment I can't find it.

Hey all:
I think I need this fix. My deal is the center vent blows cold all the time. To get heat, have to shut the center vent and use either the defroster or footwell vents.
Can anyone find the fix it link?
Thanks in advance.
Paul

[Claude]

can anyone pin this for me?

my center vents blow cool air all the time no matter where i set the centre wheel or the controls on the climate control panel. except on warm/hot starts when it blows warm air with a tiny tiny hint of coolant for about 10 seconds and then goes back to cool again.

the defrost and lower heat vents are always blowing warm/hot air and even when i set them closed there is a tiny bit of heat coming out.

all this no matter what i set the controls to... the fan just blows it softer or harder (errr...). i'm thinking i could have screwed something up when i installed my stereo and had the center vents out or when i took the 'sword' out to change the microfilter that i don't have. or maybe my heater valves got stuck over the winter. it used to work great i can't really say exactly when it happened it was over the winter and i always had the heat on.

help would be appreciated it's getting hot in here!

You have 2 different problems:

1) Cold air all the time through the center vent and no reduction of cold air when you play with the center wheel bring me to the step motor controlled by the center wheel, that's this step motor that controls the flap that lets pass more or less fresh air (cold air) to mixe with hot air in the center vent. As mentioned by someone else the fixture of this particular step motor is prone to break, when this happend the set motor lose it's reference positions and may let the flap that it controls wide open all the time. You may reach this step motor from the passenger side footwell, have to get out the glovebox before. This step motor is located just behind the OBC. You may see if the flap in question and if it stay open, just have to pull of the grid (big center vent) over the dash and look through it.

2) Hot air all the time means probable defective heather valves, they stay open all the time, that's their normal condition (no voltage on it = open valve). First you'll have to check if those valves are really bad or not. There is a 3 pins connector on the valve assembly, the center pin is the one that receives a permanent 12 volts when the SW is ON, the others two pins (one for the left valve one for the right valve) received each a pulsed ground condition from the control module located under the dash just behind the sword. So raise this connector and with and ohm meter check for continuity between the center pin and the other ones. Or applie 12 volts to the center pin and flash a ground on the other one (left or right) if the valve is OK you will hear the "clacking" noise. If the valves checks OK before comdemning the control module (1HKR1) check if the valves connector make good contacts.

Good luck.

[Jehu]

Hey all:
I think I need this fix. My deal is the center vent blows cold all the time. To get heat, have to shut the center vent and use either the defroster or footwell vents.
Can anyone find the fix it link?
Thanks in advance.
Paul


Stepper Motors?

[attack eagle]

that or the damned thumbwheel control got filthy/broken.

when you hit override hot, that does nothing to change the temp??

[525i winter driver]

Hey all:
I think I need this fix. My deal is the center vent blows cold all the time. To get heat, have to shut the center vent and use either the defroster or footwell vents.
Can anyone find the fix it link?
Thanks in advance.
Paul
don't want to scare you for no reason but this (http://www.bimmernut.com/forum/showthread.php?t=38910&highlight=p%2Fn+sword) is what ended up happening to me... it was a short either in the plug or the sword.

fixed with a new sword.... i don't think you have a sword though i think you have the resistor.

bruno's site has the best info here (http://www.bmwe34.net/Wiki/tiki-index.php?page=Fan+Blower+and+Sword)... good luck!

*-added link

[93 525 Paul]

Cold air all the time through the center vent and no reduction of cold air when you play with the center wheel bring me to the step motor controlled by the center wheel, that's this step motor that controls the flap that lets pass more or less fresh air (cold air) to mix with hot air in the center vent. As mentioned by someone else the fixture of this particular step motor is prone to break, when this happened the set motor lose it's reference positions and may let the flap that it controls wide open all the time. You may reach this step motor from the passenger side foot well, have to get out the glovebox before. This step motor is located just behind the OBC. You may see if the flap in question and if it stay open, just have to pull of the grid (big center vent) over the dash and look through it.

Good luck.

Thanks Claude. Will give it a try. It's 80* in Central CA right now, so this hasn't been an issue, but the cold is coming so I need to get on it.
Thanks again,
Paul