HVAC Issue
Thread Starter
Racer
Joined: Mar 2011
Posts: 337
Likes: 1
From: Mechanicsville Md
HVAC Issue
I got a 2002 coupe stock. During the mornings it's pretty cold so I turn the heater on 75 degrees. As the car heats up so goes the heat. About 15 min into the drive, the drivers side heat begins to go cold. The passenger side (Dual heat) stays at temp. Checked the anti freeze and it's good and I have no codes. If someone knows or experienced this before please help me out. Thanks.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Did you pull the codes via the DIC? As the car heats up, depending on how cold it is, it may dump a lot of heat, then start cooling off to the normal selected temperature. Now if your AC isn't working, it may not be able to properly control the temperature either. Is the AC light flashing or staying out and if so, what is the outside temperature at the time? Normally it won't run the AC if below 44 or so.
Thread Starter
Racer
Joined: Mar 2011
Posts: 337
Likes: 1
From: Mechanicsville Md
I didn't pull the codes with the car running. I assumed that if a code was set either running or not you would get a H code when running the codes. The outside temp in the morining has been running about 35-40. No blinking light on the AC button. I use manual mode mostly, AC works fine in the summer. I was wondering if it was the cabin temp sensor not working correctly. Any help would be greatly appreciated. Thanks
Tech Contributor
Joined: Jan 2007
Posts: 19,246
Likes: 1,095
From: Dyer, IN
I didn't pull the codes with the car running. I assumed that if a code was set either running or not you would get a H code when running the codes. The outside temp in the morining has been running about 35-40. No blinking light on the AC button. I use manual mode mostly, AC works fine in the summer. I was wondering if it was the cabin temp sensor not working correctly. Any help would be greatly appreciated. Thanks
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Ok, so your outside temperature is 35-40 so the AC will not turn on, if you are set in the "Auto" mode. You set your inside temp to 75 and the car heats up nice but then starts to cool back down inside on the driver's side but the passenger side stays good. So, this all points to the driver's side HVAC actuator which is why I asked for you to pull the codes via the DIC which will show the HVAC codes. Using a store-bought code reader, it will not pull codes from anything other than the PCM. I read in here somewhere that there is a reset procedure for the hvac but other than pulling its fuse or disconnecting the battery, I truly don't know what the procedure is. The inside temperature is measured directly in front of driver's right knee by a thermistor there. If its having a problem, I'm not sure what the result might be other than the wrong temperatures but I would think the passenger side would be impacted as well.
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
Does it do the same thing in auto mode? And yes, I have had this happen, and it was the drivers side actuator, but with codes. Without being insulting, how are you getting your codes? Also, if the AC temp is working fine in the summer, would that not tell you that perhaps the cabin sensor is or was working ok? IF no codes are present, you should probably try reseting the actuators as mentioned above, and see what happens. It would be the easiest and least expensive place to start.
Thread Starter
Racer
Joined: Mar 2011
Posts: 337
Likes: 1
From: Mechanicsville Md
NO worries. Both of you are helpful. I got checked the codes via the cars DIC. No HVAC codes or PCM codes. How do I reset the actuator? I don't want to mess with the passengers side as it apprears to be working correctly. Thanks.
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Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
There is a fuse on the passenger side floor, just find the one for the HVAC (really don't remember the number, but its in the fuse cover). I believe you pull it out for like a minute and then replace. You can't just do one actuator. If that doesn't work, do a search, I recall there is an excellent article by Bill Curlee on resetting them.
Last edited by dmarkshark; Dec 9, 2011 at 11:03 PM.
Melting Slicks
Joined: Oct 2007
Posts: 2,373
Likes: 423
I have a similar complaint but I'm not sure there is anything wrong. Since there are no codes the actuators are working within parameters. Once the car warms up, the heater changes to cool air from the upper vents and warmish air coming out the bottom vents.
The problem is with the driver's side footwell venting arrangement. One of my legs is frying and the other is frozen. The vent points directly to the left leg and there is nothing going to the right leg. I've taken to using cruise control and huddling to one side of the footwell. I still walk funny when I get to my destination while the circulation restores.
I do appreciate the cool air in my face. I haven't had a car that did that since my TR4. The heater worked better in that car though. You could keep your feet warm and your head cool and alert.
I've thought of modifying the plastic molded footwell vent but I don't want to destroy the resale or collectability of the C5.
The problem is with the driver's side footwell venting arrangement. One of my legs is frying and the other is frozen. The vent points directly to the left leg and there is nothing going to the right leg. I've taken to using cruise control and huddling to one side of the footwell. I still walk funny when I get to my destination while the circulation restores.
I do appreciate the cool air in my face. I haven't had a car that did that since my TR4. The heater worked better in that car though. You could keep your feet warm and your head cool and alert.
I've thought of modifying the plastic molded footwell vent but I don't want to destroy the resale or collectability of the C5.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I'm sort of wondering if you have an AC problem that's causing this with your heater. Since the AC runs in the Auto mode unless the outside temp gets down to about +44, which the AC shuts off at or about, I'm thinking of the summer issues where one side is warm and the other is cold due to the AC not being fully charged? So, taking that a step further in the winter, if the AC is on, then I suppose its possible for this to happen. I'm thinking a very simple way to find out would be to manually put the system into the manual mode by selecting some mode other than defrost, then turning off the AC button and see if both sides heat up normally? The other possibility is the driver's side acutator just isn't closing properly or getting stuck but not enough to post a code in the computer.
Thread Starter
Racer
Joined: Mar 2011
Posts: 337
Likes: 1
From: Mechanicsville Md
I don't know if you got confused with another post but my AC works great both sides in the summer and is equal in both auto and manual. My heat issue is in manual and auto. Mostly run in manual. I'll say one thing though, when I turn the heat up, it gets hot. Too hot to keep it high. I did notice that it works OK when in the heat (feet) but middle and feet, the middle vent goes cold.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Maybe the HVAC controller is having issues. Have you verified the vacuum lines from it are all there properly connected? Its up under the dash, passenger side. Your issues are strange to say the least. Bill Curlee has a good picture of the entire system out of the car so you might want to look at it using the search function.
Thread Starter
Racer
Joined: Mar 2011
Posts: 337
Likes: 1
From: Mechanicsville Md
I left Bill a message to have him repost his page for HVAC reset. The only question I got is to reset the HVAC actuators, all you have to do is remove the #27 fuze for about 10 min? Thanks for the help.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Most likely or just disconnect the battery. I doubt you have to wait any longer than 30 seconds or so though. I'm wondering if the blend door is working correctly therefore the question about the controller vacuum lines.