HVAC Dual Zone Controller
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
HVAC Dual Zone Controller
I am searching for answers to the many, and always changing problems that have to do with my AC . How many of you have had to replace your head unit and why, and did it fix the problems? Mine (99 Vert) is acting so squirly that I don't know whats left to look at. I am at the point now that when I hit the reset for H codes, it does nothing. I had the AC charged this weekend, now it blows warm, both sides, and the AC light stays on? I am pretty sure the clutch is engaging as I can feel it when I turn it off and on. Any help and suggestions (useful ones) would be appreciated.
Tech Contributor
Joined: Jan 2007
Posts: 19,353
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From: Dyer, IN
I am searching for answers to the many, and always changing problems that have to do with my AC . How many of you have had to replace your head unit and why, and did it fix the problems? Mine (99 Vert) is acting so squirly that I don't know whats left to look at. I am at the point now that when I hit the reset for H codes, it does nothing. I had the AC charged this weekend, now it blows warm, both sides, and the AC light stays on? I am pretty sure the clutch is engaging as I can feel it when I turn it off and on. Any help and suggestions (useful ones) would be appreciated.
1) post your codes
2) You need to know if the compressor is engaging...."pretty sure" doesn't help. Just takes a second to verify visually....then you can move on.
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
First of all, Thank you for responding to this. Here is what I have.
1) codes ( these are the only ones on the car) BO361H, and BO441H. I have had these two codes on and off since I bought the car this past summer. I replaced the drivers side actuator(it was actually missing), compressor, lines and dryer. Every once in a while it will come up with a HC code on either one, but then goes away when I reset and does not come back.
2) When I turn on the Auto, the Ac and compressor come on and stay on. When I turn it off, it stops. At this moment, I think if left alone the compressor would stay on as all I am getting is warm air in the cabin, on both sides.
1) codes ( these are the only ones on the car) BO361H, and BO441H. I have had these two codes on and off since I bought the car this past summer. I replaced the drivers side actuator(it was actually missing), compressor, lines and dryer. Every once in a while it will come up with a HC code on either one, but then goes away when I reset and does not come back.
2) When I turn on the Auto, the Ac and compressor come on and stay on. When I turn it off, it stops. At this moment, I think if left alone the compressor would stay on as all I am getting is warm air in the cabin, on both sides.
Last edited by dmarkshark; Mar 23, 2011 at 08:24 AM.
Tech Contributor
Joined: Jan 2007
Posts: 19,353
Likes: 1,125
From: Dyer, IN
First of all, Thank you for responding to this. Here is what I have.
1) codes ( these are the only ones on the car) BO361H, and BO441H. I have had these two codes on and off since I bought the car this past summer. I replaced the drivers side actuator(it was actually missing), compressor, lines and dryer. Every once in a while it will come up with a HC code on either one, but then goes away when I reset and does not come back.
2) When I turn on the Auto, and Ac and compressor come on and stay on. When I turn it off, it stops. At this moment, I think if left alone the compressor would stay on as all I am getting is warm air in the cabin, on both sides.
1) codes ( these are the only ones on the car) BO361H, and BO441H. I have had these two codes on and off since I bought the car this past summer. I replaced the drivers side actuator(it was actually missing), compressor, lines and dryer. Every once in a while it will come up with a HC code on either one, but then goes away when I reset and does not come back.
2) When I turn on the Auto, and Ac and compressor come on and stay on. When I turn it off, it stops. At this moment, I think if left alone the compressor would stay on as all I am getting is warm air in the cabin, on both sides.
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
It blew med cold. The reason I took it in was because the AC was going on and off every 2 seconds. It did this after I got it worked on in Sept/Oct. The guy said it was fine, but I figured he was never going to get it right and moved on. During the cooler months (Dallas cool) the AC would stay on, but only when it got above 70 ish would it start the on and off thing. I figured it was low on freon, took it in and they put .50 of freon in. Then it blew warm on the drivers side and they had no clue. I figured the code was coming up again, and it was. I tried to reset it, but now it would not reset, so I took the actuator out again, (its the new model) and plugged it in, watched it turn, put it back in, and all was well. But it was blowing warm today(both sides) and started throwing the codes as stated above. I think I will take it back and have the freon checked again, just to be sure. But, if it were low, the AC would not stay engaged would it?
Last edited by dmarkshark; Mar 22, 2011 at 11:41 PM.
Tech Contributor
Joined: Dec 2006
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From: Van Buren Arkansas
Wounded Warrior Escort '11
The codes sounds like the driver's side actuator has problems. Usually the gear cracks inside of it. Its a PITA to get too but it can be done. Answer Lucky's questions first as he's pretty sharp.
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
Actually, I have a new actuator that I put on in July. The old one was gone, just a connector hanging loose. I took the actuator out again this weekend to check, but did not want to try and open it up(not sure if I can), but did check for the wiring and stuff. When I put it back on, the codes went away. I started it several times with the AC and no codes. I figured that was it. Today, though, it again started throwing the codes and warm air on both sides, so I guess that wasn't it. The thing is, the AC will stay on while giving me the warm air?
Last edited by dmarkshark; Mar 23, 2011 at 08:26 AM.
Tech Contributor
Joined: Dec 2006
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From: Van Buren Arkansas
Wounded Warrior Escort '11
Well, the AC will stay on if the system is set in the "Auto" mode. The AC sucks the moisture out of the air. Same goes for when you select the defrost mode...it automatically insures the AC is running. If you wish to manually control the HVAC, you need to turn off the Auto mode by selecting airflow desires, temperature, fan settings and so on. The system was designed to run in Auto. Now the AC will shut off when the outside temp gets down to around 43 and below. That's not an absolute low temp shutoff rather a range as its dependent on other factors as well.
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Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
I understand that, I guess what I meant was that it keeps running, so its probably not low on freon? Would that be a correct assumption? I am just trying to reason why it would all of a sudden start blowing warm air(both sides), after I just had it charged and I figured since the AC was running the charge was probably ok( or maybe too much), because when the freon is low the compressor will turn off, is that not correct? ( I am in Dallas area, so its in the 70's here) . Also, if the AC was working correctly, I would get cold on the passanger side at least, even if I had the codes on the drivers side.
Tech Contributor
Joined: Dec 2006
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From: Van Buren Arkansas
Wounded Warrior Escort '11
If the compressor is actually running, it might not be low on refrigerant (Halogen R-134, Freon R-12 is no longer used). I would look at the vacuum line feeding the HVAC which comes from the rear of the intake manifold at the MAP sensor, routes along the firewall to down behind the battery where it goes through the firewall itself. It can crack or be damaged from battery acid issues. Also look under the dash pad for it on the right side and see if its connected to the vcauum distribution at the controller.
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
Yep, I am not an expert at this, but I do have a set of gauges (with directions) and plan to look at it tonight and see if I can figure it out. At least, I can see if the charge is good, and then I can use that as a starting point. I know there is a good sticky on the AC so I can use that, and see what happens. Thanks again Y'all.
Melting Slicks
Joined: Sep 2006
Posts: 2,736
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From: Redding CA
Well, the AC will stay on if the system is set in the "Auto" mode. The AC sucks the moisture out of the air. Same goes for when you select the defrost mode...it automatically insures the AC is running. If you wish to manually control the HVAC, you need to turn off the Auto mode by selecting airflow desires, temperature, fan settings and so on. The system was designed to run in Auto. Now the AC will shut off when the outside temp gets down to around 43 and below. That's not an absolute low temp shutoff rather a range as its dependent on other factors as well.
I ask because these last few mornings have been abnormally cold..when I turn the defrost on, my AC isn't automatically kicking on like normal?...even if I try and push the AC button and kick it on manually while the defrost is on, the light just blinks a couple of times then goes out.
No codes. I haven't checked the R 134A level yet but will soon because summer is just about here.
Tech Contributor
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From: Van Buren Arkansas
Wounded Warrior Escort '11
The defrost uses refrigerated air to get rid of condesation on the insides of the windows therefore the AC runs...however, if the outside temp falls below the magic numbers, the AC isn't needed so it doesn't turn on, by design.
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
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From: Rockwall TX
dgrant: Thanks, This is a good idea. Not sure that it will address my issue as I can change the places where the air comes from. Also, when I got the car, I had the oil pressure sending unit replaced, and while he was in there I also had a new vacuum line put in. But, I will look at that after I check the AC pressures. But, I won't get to it until tomorrow. But thanks, I appreciate all of the help I can get. I will post back here when I get some numbers.
Safety Car
Joined: Sep 2000
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From: Taildragers rule! USA1
Did not know this...is this true even if you're on DEFROST or try and manually turn the AC on?
I ask because these last few mornings have been abnormally cold..when I turn the defrost on, my AC isn't automatically kicking on like normal?...even if I try and push the AC button and kick it on manually while the defrost is on, the light just blinks a couple of times then goes out.
No codes. I haven't checked the R 134A level yet but will soon because summer is just about here.
I ask because these last few mornings have been abnormally cold..when I turn the defrost on, my AC isn't automatically kicking on like normal?...even if I try and push the AC button and kick it on manually while the defrost is on, the light just blinks a couple of times then goes out.
No codes. I haven't checked the R 134A level yet but will soon because summer is just about here.
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
Ok, I came home and put the gauges on, now can someone help me interpret what the numbers mean. Thanks in advance.
Static #s LO 78 PSI HI 80 PSI
2000 RPM Lo 30 Psi Hi 126 Psi
Temp 75 Hum. 21
It looks like these are ok from what I see in my manual? The strange thing is yesterday when I ran the system it only blew hot, along with the BO361 and BO441 H codes. Today , I start it, do the AC reading, reset the H codes, turn it off, come back later and start it with no codes coming on and med cool air coming out. Which, brings me back to my original question. Do I possibly have a flakey control unit?
Static #s LO 78 PSI HI 80 PSI
2000 RPM Lo 30 Psi Hi 126 Psi
Temp 75 Hum. 21
It looks like these are ok from what I see in my manual? The strange thing is yesterday when I ran the system it only blew hot, along with the BO361 and BO441 H codes. Today , I start it, do the AC reading, reset the H codes, turn it off, come back later and start it with no codes coming on and med cool air coming out. Which, brings me back to my original question. Do I possibly have a flakey control unit?
Last edited by dmarkshark; Mar 24, 2011 at 07:34 PM.
Thread Starter
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
Ok, I took it back in, they vacuumed the system, put the freon back in, same amount , no leaks. They said it was all working and should be cooling off but its not. Probably should have done this the first time, but I plan on taking it to Corvette World and see if they can figure this one out.
Thanks
Thanks
Tech Contributor
Joined: Dec 2006
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From: Van Buren Arkansas
Wounded Warrior Escort '11
There is a vacuum line feeding the main diverter valve which I think is the hot/cold blend air valve. From there, (guessing) it goes to the diverter valves which are electrically controlled but two actuators. The vacuum line that I mentioned before, needs to be verified that its not leaking. If you look it where it enters the firewall from the engine side, you should be able to find it on the inside and verify that its actually has vacuum on it, therefore not broke or cracked. There is a vacuum distribution device on the inside that it feeds which I would think would be the perfect place to check this.