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Jim Cash
01-20-1999, 03:27 PM
>Jim: A while back you posted some ideas about this problem. We are now struggling with it on the<br>E34 board which I don't know if you are following. So...can you help with this? If you want to<br>post on the E34 board we would appreciate any advice.<p>Thanks,<br>Jon Brush '92 535i 5sp 67.9Kmi<p><br>>>Posted by Taft on January 19, 1999 at 16:47:52:<p>I have followed the various threads of no heat from the center vent (above the radio), but they<br>have not helped. In my 94 530i, I get no heat, regardless of the thumbwheel position (other heat<br>works fine). I pulled out the radio and the OBC and got to the wiring harness that goes to the<br>thumbwheel (I hope!). I checked the resistance from the three leads and the resistance did not<br>change when I turned the wheel. I could not seem get the thumbwheel out- it is attached to the<br>center vent which does come out easily. So, is there an easy way to remove the center<br>vent/thumbwheel (Bentley doesn't help)? Thanks <br>-------------------------------------<p>Response from Jim Cash as requested.<p>I dont follow the E34 board because I never had that model. <p>But - regarding your question about the temperature control thumbwheel on the centre vent. According to a smal parts drawing i have it appears to operate the same way as on the E39. I do not know what wires you are testing but there are no electrical wires to the thumbwheel - it is mechanical. It is a ttached to a shrot beldon cable that goes to a vent flap arm somewhere on the Heater unit. All it does is adjust a flap to allow some air from the heater plenum to cross over into the fresh air vents (the front ducts on the dash, including at the doors).<p>Normally there is no heat to those vents, just fresh air, or chilled air when the AC is on. The blending flap (controlled by that wheel) is to help take some of the chill off that air in winter.<p>If yours is not working I suspect that the vent flap is no longer being moved by the cable - look for the end of the cable by the heater and see if the cable is disconnected, or come loose from it's fastening. The end of the outer part of the cable must be held in a clamp arragement, so that the inner control wire can move to control the vent flap arm.<p>I do not know how to remove the centre vent from the E34 dash, but if it is anything like the E39 there are some small plastic tabs around the outside rear that hold the unit in place. I had to get my hand up above and behind the unit to release the tabs on mine - easy when you can go through the airbag opening - I do not know how to do it on the E34.<p>Hope that helps a bit.<p>Cheers<p>Jim Cash<br>London, Ontario, Canada<p><br>

Jon Brush
01-20-1999, 05:19 PM
Thanks a bunch, Jim!<br>Jon Brush<p>: >Jim: A while back you posted some ideas about this problem. We are now struggling with it on the<br>: E34 board which I don't know if you are following. So...can you help with this? If you want to<br>: post on the E34 board we would appreciate any advice.<p>: Thanks,<br>: Jon Brush '92 535i 5sp 67.9Kmi<p>: <br>: >>Posted by Taft on January 19, 1999 at 16:47:52:<p>: I have followed the various threads of no heat from the center vent (above the radio), but they<br>: have not helped. In my 94 530i, I get no heat, regardless of the thumbwheel position (other heat<br>: works fine). I pulled out the radio and the OBC and got to the wiring harness that goes to the<br>: thumbwheel (I hope!). I checked the resistance from the three leads and the resistance did not<br>: change when I turned the wheel. I could not seem get the thumbwheel out- it is attached to the<br>: center vent which does come out easily. So, is there an easy way to remove the center<br>: vent/thumbwheel (Bentley doesn't help)? Thanks <br>: -------------------------------------<p>: Response from Jim Cash as requested.<p>: I dont follow the E34 board because I never had that model. <p>: But - regarding your question about the temperature control thumbwheel on the centre vent. According to a smal parts drawing i have it appears to operate the same way as on the E39. I do not know what wires you are testing but there are no electrical wires to the thumbwheel - it is mechanical. It is a ttached to a shrot beldon cable that goes to a vent flap arm somewhere on the Heater unit. All it does is adjust a flap to allow some air from the heater plenum to cross over into the fresh air vents (the front ducts on the dash, including at the doors).<p>: Normally there is no heat to those vents, just fresh air, or chilled air when the AC is on. The blending flap (controlled by that wheel) is to help take some of the chill off that air in winter.<p>: If yours is not working I suspect that the vent flap is no longer being moved by the cable - look for the end of the cable by the heater and see if the cable is disconnected, or come loose from it's fastening. The end of the outer part of the cable must be held in a clamp arragement, so that the inner control wire can move to control the vent flap arm.<p>: I do not know how to remove the centre vent from the E34 dash, but if it is anything like the E39 there are some small plastic tabs around the outside rear that hold the unit in place. I had to get my hand up above and behind the unit to release the tabs on mine - easy when you can go through the airbag opening - I do not know how to do it on the E34.<p>: Hope that helps a bit.<p>: Cheers<p>: Jim Cash<br>: London, Ontario, Canada<p><br>

Taft
01-21-1999, 10:07 AM
OK, thanks, maybe this is working as designed and I shouldn't mess with it. Is anyone getting heat (I mean really warm air) out of thier center vents (in cold weatehr)?<p>Thanks<p>Taft<p>: Thanks a bunch, Jim!<br>: Jon Brush<p>: : >Jim: A while back you posted some ideas about this problem. We are now struggling with it on the<br>: : E34 board which I don't know if you are following. So...can you help with this? If you want to<br>: : post on the E34 board we would appreciate any advice.<p>: : Thanks,<br>: : Jon Brush '92 535i 5sp 67.9Kmi<p>: : <br>: : >>Posted by Taft on January 19, 1999 at 16:47:52:<p>: : I have followed the various threads of no heat from the center vent (above the radio), but they<br>: : have not helped. In my 94 530i, I get no heat, regardless of the thumbwheel position (other heat<br>: : works fine). I pulled out the radio and the OBC and got to the wiring harness that goes to the<br>: : thumbwheel (I hope!). I checked the resistance from the three leads and the resistance did not<br>: : change when I turned the wheel. I could not seem get the thumbwheel out- it is attached to the<br>: : center vent which does come out easily. So, is there an easy way to remove the center<br>: : vent/thumbwheel (Bentley doesn't help)? Thanks <br>: : -------------------------------------<p>: : Response from Jim Cash as requested.<p>: : I dont follow the E34 board because I never had that model. <p>: : But - regarding your question about the temperature control thumbwheel on the centre vent. According to a smal parts drawing i have it appears to operate the same way as on the E39. I do not know what wires you are testing but there are no electrical wires to the thumbwheel - it is mechanical. It is a ttached to a shrot beldon cable that goes to a vent flap arm somewhere on the Heater unit. All it does is adjust a flap to allow some air from the heater plenum to cross over into the fresh air vents (the front ducts on the dash, including at the doors).<p>: : Normally there is no heat to those vents, just fresh air, or chilled air when the AC is on. The blending flap (controlled by that wheel) is to help take some of the chill off that air in winter.<p>: : If yours is not working I suspect that the vent flap is no longer being moved by the cable - look for the end of the cable by the heater and see if the cable is disconnected, or come loose from it's fastening. The end of the outer part of the cable must be held in a clamp arragement, so that the inner control wire can move to control the vent flap arm.<p>: : I do not know how to remove the centre vent from the E34 dash, but if it is anything like the E39 there are some small plastic tabs around the outside rear that hold the unit in place. I had to get my hand up above and behind the unit to release the tabs on mine - easy when you can go through the airbag opening - I do not know how to do it on the E34.<p>: : Hope that helps a bit.<p>: : Cheers<p>: : Jim Cash<br>: : London, Ontario, Canada<p><br>

Andy Peavy
01-21-1999, 10:28 AM
Yes. I do not move mine but twice a year. Once in the fall. When it gets cold, I move it to the red/warm setting. This way, the foot vents and the center vents are at the same temp.<p>In the spring, when I start using the fan or A/C to cool the car, I move the vent to blue/cool.<p>In any event, mine adjusts the temp on the upper vents relative to the foot vents which are adjusted by the HVAC control knobs.<p>Andy Peavy<br>91 535i<br>email: apeavy@yahoo.com<p><i>: OK, thanks, maybe this is working as designed and I shouldn't mess with it. Is anyone getting heat (I mean really warm air) out of thier center vents (in cold weatehr)?<p>: Thanks<p>: Taft<br></i>

Jon Brush
01-21-1999, 12:45 PM
My center vent used to work like Andy's and I really liked it. I could send warm or cool air to my face while still having warm feet and a defogged windshield; good for alertness.. Mine stopped sending warm or hot air when I tried it this fall, only cold air as you describe. I think there must be a problem with the cable or the vent flap which Jim Cash describes; I just haven't had time to look at it, so I keep the dash vents closed during the winter.<br>Regards, <br>Jon Brush<br>'92 535i 5sp 68Kmi<br>: Yes. I do not move mine but twice a year. Once in the fall. When it gets cold, I move it to the red/warm setting. This way, the foot vents and the center vents are at the same temp.<p>: In the spring, when I start using the fan or A/C to cool the car, I move the vent to blue/cool.<p>: In any event, mine adjusts the temp on the upper vents relative to the foot vents which are adjusted by the HVAC control knobs.<p>: Andy Peavy<br>: 91 535i<br>: email: apeavy@yahoo.com<p>: : OK, thanks, maybe this is working as designed and I shouldn't mess with it. Is anyone getting heat (I mean really warm air) out of thier center vents (in cold weatehr)?<p>: : Thanks<p>: : Taft<p>

Bary
01-21-1999, 10:09 PM
<i>: OK, thanks, maybe this is working as designed and I shouldn't mess with it. Is anyone getting heat (I mean really warm air) out of thier center vents (in cold weatehr)?<p>: Thanks<p>: Taft<p>On my 1990 535i the center vent is giving me all the heat I want (hot in red zone blending to cold when moving the knob towards the blue zone)in fact in hot position it gives me the same temperature as the defrost and foot vents and can be brought gradualy to full cold. When i say full cold, I mean it, it was -40 (C or F degrees is the same at -40) last week where i live. I realy appreciate that feature.<p>Bary


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