Automatic Climate Control
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Automatic Climate Control
Kind of hard to explain this, but I think I have a problem with my climate control system. Whenever I turn on my heaters, all I get is constant coolish warm air coming out of the vents. The temperature settings between 61 to 85 feels the same. But from 85 to 90, there is some heat coming out, but not hot. I would think that if the system is operating normal, the temperature should get a little hotter with each digit going up in increments. The car was definitely warmed up and the AC was OFF. Has anyone ever experienced this before?
Le Mans Master
Joined: Oct 2000
Posts: 6,462
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From: Sausalito CA
There is a movable vent door in the AC tubing/ channeling that I recall has a failure rate as written about in other threads.
Confirm your diagnosis with a thermometer.
Yes, there is a noticable temp difference between 61 and 85 on the setting.
Confirm your diagnosis with a thermometer.
Yes, there is a noticable temp difference between 61 and 85 on the setting.
Team Owner
Joined: Sep 2005
Posts: 20,352
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From: Ventura County, Calif
As Kenny said, it's likely a mode actuator door. But you should go to a dealer, or independent mech who has a Tech II, to pull HVAC codes to help diagnose for sure.
If it is diagnosed as a mode actuator, just be aware that there are 4 of them in the system. It is a common failure that we are seeing reported a lot here, especially on '05 and now '06 cars. It is about a $1500 job to replace ONE because the dash has to be removed. So, if you have to pay all that labor charge to pull the dash to replace ONE, you would be well advised to spend an extra $200 for parts to replace all 4 of them. If you don't, you can expect to go through it all again when the next one fails, might be next year, next month or next week, you just don't know. What you would know is the others will fail. We have learned that the newest replacement units have a different color material, so the speculation is the new ones might last longer, but there is no official confirmation of that.
Good luck. Hope it's something less expensive.
If it is diagnosed as a mode actuator, just be aware that there are 4 of them in the system. It is a common failure that we are seeing reported a lot here, especially on '05 and now '06 cars. It is about a $1500 job to replace ONE because the dash has to be removed. So, if you have to pay all that labor charge to pull the dash to replace ONE, you would be well advised to spend an extra $200 for parts to replace all 4 of them. If you don't, you can expect to go through it all again when the next one fails, might be next year, next month or next week, you just don't know. What you would know is the others will fail. We have learned that the newest replacement units have a different color material, so the speculation is the new ones might last longer, but there is no official confirmation of that.
Good luck. Hope it's something less expensive.
Team Owner
Joined: Sep 2000
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
The automatic system also automatically selects where the air should come out (foot, face, defrost, and various combinations). If the system is trying to heat up the car, it might be putting all of the hot air down at your feet and little or no hot air out of the higher outlets.
You can manually override the system to select where the air is coming out, you could try that and see what happens.
Also, I think the system is designed to have the A/C on (or available to be on if the system needs it), you might try turning the A/C on and see if anything changes.
Like Kenny said, a thermometer would be very helpful. And it can take a couple of minutes for things to stabilize when you change settings.
Let us know what you discover!
You can manually override the system to select where the air is coming out, you could try that and see what happens.
Also, I think the system is designed to have the A/C on (or available to be on if the system needs it), you might try turning the A/C on and see if anything changes.
Like Kenny said, a thermometer would be very helpful. And it can take a couple of minutes for things to stabilize when you change settings.
Let us know what you discover!
Race Director
Joined: Mar 2005
Posts: 10,399
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From: Austin Texas
The temp settings aren't supposed to be the temp of the air coming out of the vents. The temp setting is for the desired temp inside the car. The temp inside the car is determined by sensors in the cabin.
Ex.; If it's sunny and 75° and you set the desired temp at 75° the A/C will come on (cool air) until the interior gets to 75°. If it's sunny and 40° outside and you set the desired temp at 75° the heater (warm air) will come out of the vent until the interior temp reaches 75°.
Here in Austin I've had the A/C kick in on a sunny day when the outside temperature is 60 and the desired inside temp set at 78°. Between the heat from the exhaust and the firewall and the heat from the sun the car needs A/C on a 60° day to maintain 78° inside..
Ex.; If it's sunny and 75° and you set the desired temp at 75° the A/C will come on (cool air) until the interior gets to 75°. If it's sunny and 40° outside and you set the desired temp at 75° the heater (warm air) will come out of the vent until the interior temp reaches 75°.
Here in Austin I've had the A/C kick in on a sunny day when the outside temperature is 60 and the desired inside temp set at 78°. Between the heat from the exhaust and the firewall and the heat from the sun the car needs A/C on a 60° day to maintain 78° inside..
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The temp settings aren't supposed to be the temp of the air coming out of the vents. The temp setting is for the desired temp inside the car. The temp inside the car is determined by sensors in the cabin.
Ex.; If it's sunny and 75° and you set the desired temp at 75° the A/C will come on (cool air) until the interior gets to 75°. If it's sunny and 40° outside and you set the desired temp at 75° the heater (warm air) will come out of the vent until the interior temp reaches 75°.
Here in Austin I've had the A/C kick in on a sunny day when the outside temperature is 60 and the desired inside temp set at 78°. Between the heat from the exhaust and the firewall and the heat from the sun the car needs A/C on a 60° day to maintain 78° inside..
Ex.; If it's sunny and 75° and you set the desired temp at 75° the A/C will come on (cool air) until the interior gets to 75°. If it's sunny and 40° outside and you set the desired temp at 75° the heater (warm air) will come out of the vent until the interior temp reaches 75°.
Here in Austin I've had the A/C kick in on a sunny day when the outside temperature is 60 and the desired inside temp set at 78°. Between the heat from the exhaust and the firewall and the heat from the sun the car needs A/C on a 60° day to maintain 78° inside..
Thanks for the reply.
Last edited by TheShape8787; Feb 23, 2012 at 09:01 PM.
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Thanks
Last edited by TheShape8787; Feb 23, 2012 at 09:03 PM.
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As Kenny said, it's likely a mode actuator door. But you should go to a dealer, or independent mech who has a Tech II, to pull HVAC codes to help diagnose for sure.
If it is diagnosed as a mode actuator, just be aware that there are 4 of them in the system. It is a common failure that we are seeing reported a lot here, especially on '05 and now '06 cars. It is about a $1500 job to replace ONE because the dash has to be removed. So, if you have to pay all that labor charge to pull the dash to replace ONE, you would be well advised to spend an extra $200 for parts to replace all 4 of them. If you don't, you can expect to go through it all again when the next one fails, might be next year, next month or next week, you just don't know. What you would know is the others will fail. We have learned that the newest replacement units have a different color material, so the speculation is the new ones might last longer, but there is no official confirmation of that.
Good luck. Hope it's something less expensive.
If it is diagnosed as a mode actuator, just be aware that there are 4 of them in the system. It is a common failure that we are seeing reported a lot here, especially on '05 and now '06 cars. It is about a $1500 job to replace ONE because the dash has to be removed. So, if you have to pay all that labor charge to pull the dash to replace ONE, you would be well advised to spend an extra $200 for parts to replace all 4 of them. If you don't, you can expect to go through it all again when the next one fails, might be next year, next month or next week, you just don't know. What you would know is the others will fail. We have learned that the newest replacement units have a different color material, so the speculation is the new ones might last longer, but there is no official confirmation of that.
Good luck. Hope it's something less expensive.
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Tech Contributor
Joined: Oct 1999
Posts: 40,999
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From: Charlotte, NC (formerly Endicott, NY)
What does your outside temperature display indicate when you are having this problem? If it doesn't update soon enough after an engine stop it will keep the system from making changes until it is updated. Check this write up on how the system controls temperature.
You should also go someplace that can read the codes. Need a Tech 2 or equivalent high end scanner that the Joe Blow shop typically can't afford so you may be limited to the dealer shop.
The actuators may have lost their calibration and all that may be required is to have a Tech 2 recalibrate them.
Bill
You should also go someplace that can read the codes. Need a Tech 2 or equivalent high end scanner that the Joe Blow shop typically can't afford so you may be limited to the dealer shop.
The actuators may have lost their calibration and all that may be required is to have a Tech 2 recalibrate them.
Bill
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From: Toronto, Canada
C7 of the Year - Unmodified Finalist 2021
Kind of hard to explain this, but I think I have a problem with my climate control system. Whenever I turn on my heaters, all I get is constant coolish warm air coming out of the vents. The temperature settings between 61 to 85 feels the same. But from 85 to 90, there is some heat coming out, but not hot. I would think that if the system is operating normal, the temperature should get a little hotter with each digit going up in increments. The car was definitely warmed up and the AC was OFF. Has anyone ever experienced this before?
Team Owner
Joined: Sep 2005
Posts: 20,352
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From: Ventura County, Calif
One thing I should have mentioned in my first post is, like Bill Dearborn said, the system may have lost calibration. One trick from the C5 guys is to disconnect the battery for 30 mins then reconnect and see if things come back correctly. Only works for some cases but it doesn't cost anything so it's probably worth a try. And if you do that remember you'll have to reindex the windows.
Thread Starter
Advanced
Joined: Jun 2011
Posts: 52
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What does your outside temperature display indicate when you are having this problem? If it doesn't update soon enough after an engine stop it will keep the system from making changes until it is updated. Check this write up on how the system controls temperature.
You should also go someplace that can read the codes. Need a Tech 2 or equivalent high end scanner that the Joe Blow shop typically can't afford so you may be limited to the dealer shop.
The actuators may have lost their calibration and all that may be required is to have a Tech 2 recalibrate them.
Bill
You should also go someplace that can read the codes. Need a Tech 2 or equivalent high end scanner that the Joe Blow shop typically can't afford so you may be limited to the dealer shop.
The actuators may have lost their calibration and all that may be required is to have a Tech 2 recalibrate them.
Bill
The outside air temp reading was 43 degrees Fahrenheit. I was bit chilly last night in Northern Califorinia. I dialed in 70 and then 80, then 85 with no change in the cabin air. But, from 85 to 90. I can feel a little heat. The A/C is off.
Thanks.
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One thing I should have mentioned in my first post is, like Bill Dearborn said, the system may have lost calibration. One trick from the C5 guys is to disconnect the battery for 30 mins then reconnect and see if things come back correctly. Only works for some cases but it doesn't cost anything so it's probably worth a try. And if you do that remember you'll have to reindex the windows.
Thanks Rick. I will disconnect the battery later tonight. Hope it works!! Don't really feel like spending $1500 to get it fixed as I can use that money toward a new exhaust system.
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Thanks. I will try that as well. I'd never knew you can do that with the HVAC controls. Hopefully this will correct it. I will keep you guys updated.
Le Mans Master
Joined: Jan 2008
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From: corpus christi Texas
???? When it is a little cold down here,i just turn the **** to 90 degrees and the heat comes from the floor vents.Thats the way it should work on AUTO.And do what post 12 said because the sensor is up front somewhere & I'm thinking it might get dirty.I've done that a few times & the temp resets.
Melting Slicks
Joined: Dec 2006
Posts: 2,694
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By the way, my car is on the way, but was wondering how do you turn HVAC off? I thought BMW was the only freaking car without an 'OFF' button. I was wrong
. On the bimmer, you have to click the fan down one more time after lowest setting. Is it the same way on the Vette? With mild TX winters, all I usually need is the vent in 'fresh' mode with the system off. Hope the Vette is not like the M3, which automatically switches to 'RECIRC' when system is off, so you have to have it on to blow any air. All my other and preivous cars allow fresh air with the system off, and the air temperature is the last selected. Thanks.
Last edited by JCtx; Feb 24, 2012 at 01:49 AM.
Le Mans Master
Joined: Jan 2008
Posts: 6,457
Likes: 297
From: corpus christi Texas
Indeed. And I HATE that. Same thing with every car with automatic climate control I've ever had. Use them in manual most of the time, especially in winter.
By the way, my car is on the way, but was wondering how do you turn HVAC off? I thought BMW was the only freaking car without an 'OFF' button. I was wrong. On the bimmer, you have to click the fan down one more time after lowest setting. Is it the same way on the Vette? With mild TX winters, all I usually need is the vent in 'fresh' mode with the system off. Hope the Vette is not like the M3, which automatically switches to 'RECIRC' when system is off, so you have to have it on to blow any air. All my other and preivous cars allow fresh air with the system off, and the air temperature is the last selected. Thanks.
By the way, my car is on the way, but was wondering how do you turn HVAC off? I thought BMW was the only freaking car without an 'OFF' button. I was wrong
. On the bimmer, you have to click the fan down one more time after lowest setting. Is it the same way on the Vette? With mild TX winters, all I usually need is the vent in 'fresh' mode with the system off. Hope the Vette is not like the M3, which automatically switches to 'RECIRC' when system is off, so you have to have it on to blow any air. All my other and preivous cars allow fresh air with the system off, and the air temperature is the last selected. Thanks.
Team Owner
Joined: Sep 2000
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
The A/C doesnt have to be on all the time. You can manually turn that off. I believe the only way that the A/C is on all the time is when you hit the AUTO button. I think leaving it on AUTO mode burns more gas as the A/C compressor is always spinning. But. I could be wrong.
Thanks
Thanks
The Auto system in our C5 was a cruel joke, but Auto in the C6 (we've had a 2006 and now a 2009) seems to work well, better than in any of the other cars we've had. I leave ours in Auto virtually all the time, and I suspect that the whole system was designed and calibrated to operate that way most of the time.
I'd recommend trying Auto and A/C on for a bit, see if that changes anything on the air vent temps. Good or bad, it will be another data point for troubleshooting.
Good luck!
Le Mans Master
Joined: Jan 2011
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St. Jude Donor '11-'12-'13-'14-'15-'16-'17
This is number one. 
Is the car warm? Forget what the air 'feels' like!
My car is set at all the time at 70 (both sides) and on Auto. I never feel a 'blast' of heat any more than a 'blast' of cold air. As things get going, the fan is fairly high but settles down to a whisper, maintaining the set temp (more or less as I've never verified exact temps).
Is the car warm? Forget what the air 'feels' like! My car is set at all the time at 70 (both sides) and on Auto. I never feel a 'blast' of heat any more than a 'blast' of cold air. As things get going, the fan is fairly high but settles down to a whisper, maintaining the set temp (more or less as I've never verified exact temps).