HVAC blowing hot driver's side only
02-25-2012, 04:55 PM
#1
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HVAC blowing hot driver's side only
Driving a 2000 vette, FYI.
Long story short, I'm getting hot air out of my driver's side vents only when I have the A/C on (I'm in central Texas, so it is hot enough to need A/C sometimes). Cool air's coming out of the passenger side.
I've had my freon level checked. It's where it should be.
I've checked for HVAC codes in the DIC. No codes present. Don't even have a history of any, let alone actuator codes.
Tried pulling fuse #18 and #27 to get reset the actuator positions. That didn't work.
Tried disconnecting the battery for a few minutes. Sounded like they did re-calibrate, but still the same problem.
There are two possible factors that could be at play, but probably aren't the cause. I noticed this problem after I had re-installed an aftermarket stereo, which I had the battery disconnected for an extended time while doing so, obviously. I've also had my originally compressor fail about two years ago. Since then, I've gone though two other compressors, because I'm pretty sure my mechanic did not get all the shards from the original compressor of the system, and it keeps junking up the new compressors. Right now, the compressor currently installed is failing also. But even when I had trouble with previous compressors, I still had cold air blowing out of all vents.
So, I'm pretty much at this stage right now -->
Anybody have others suggestions of what could be going on?
Long story short, I'm getting hot air out of my driver's side vents only when I have the A/C on (I'm in central Texas, so it is hot enough to need A/C sometimes). Cool air's coming out of the passenger side.
I've had my freon level checked. It's where it should be.
I've checked for HVAC codes in the DIC. No codes present. Don't even have a history of any, let alone actuator codes.
Tried pulling fuse #18 and #27 to get reset the actuator positions. That didn't work.
Tried disconnecting the battery for a few minutes. Sounded like they did re-calibrate, but still the same problem.
There are two possible factors that could be at play, but probably aren't the cause. I noticed this problem after I had re-installed an aftermarket stereo, which I had the battery disconnected for an extended time while doing so, obviously. I've also had my originally compressor fail about two years ago. Since then, I've gone though two other compressors, because I'm pretty sure my mechanic did not get all the shards from the original compressor of the system, and it keeps junking up the new compressors. Right now, the compressor currently installed is failing also. But even when I had trouble with previous compressors, I still had cold air blowing out of all vents.
So, I'm pretty much at this stage right now -->
Anybody have others suggestions of what could be going on?
02-25-2012, 05:18 PM
#2
Burning Brakes
It sounds like your AC, if its low on freon it may still cool on the passenger side but not enough for the drivers side. It sounds like you need to find a better mechanic, probably need to have the system checked and flushed, and recharged. I had that problem, (bad mechanic), found a good one, he flushed the system (the orifice tube had been put in backwards to boot), and its still working good. Good luck.
02-25-2012, 05:24 PM
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It sounds like your AC, if its low on freon it may still cool on the passenger side but not enough for the drivers side. It sounds like you need to find a better mechanic, probably need to have the system checked and flushed, and recharged. I had that problem, (bad mechanic), found a good one, he flushed the system (the orifice tube had been put in backwards to boot), and its still working good. Good luck.
02-27-2012, 10:08 AM
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I guess this is a new symptom, or one I just discovered: the driver's side will still only blow vent air, even though I have the heater on. Passenger side still works as it should.
Is that still a sign of low freon?
Is that still a sign of low freon?
02-27-2012, 12:15 PM
#6
Melting Slicks
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Remove the positive batt cable for about 5 min. you may have to do it more then once.
I had the same thing happen on an Olds Intrigue that the batt took a dump in.
Had to do it 3 times for it to work.
03-25-2012, 07:20 PM
#8
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Vacuum issue
Have you checked the vacuum lines that control the air flow in the dash ? Usually this issue is a leak in the vacuum system. Lots of history of the vacuum line between the back of the manifold and the vacuum tank in the passenger side fender being damaged due to battery acid leaking. You will need to remove the battery and battery tray to check the wire bundle (s) underneath the battery tray. The vacuum line is in one of the larger bundles.
I had air coming out of all vents on the Ac or Heat. It was suggested that it is the vacuum supply line coming from the back of the manifold that is the culprit - Because Battery Acid Leaks on it and it burns through. Well this is what happened or perhaps just it was rubbing and rubbed through thus allowing "NO" vacuum to get to the HVAC Vacuum manifold. (It did not have any Acid residue on it at all).
This vacuum line is "HARD" plastic and not easy to locate WHY? because it is within the wire loom going down to the area behind the passenger front wheel that goes to the PCM.
This vacuum line is "HARD" plastic and not easy to locate WHY? because it is within the wire loom going down to the area behind the passenger front wheel that goes to the PCM.
To Begin:
I had to jack up the front end of the Vette and turn the wheel all the way to the left, so I could remove the panel to access the area by the PCM and Vacuum junction One Way Check Valve.
You "WILL" need to take all the 7mm nuts off the panel (The ones underneath too) AND the last one for the fender on the bottom furthest toward the rear of the Vette right next to the door!
This is because you will need to pull a little on the fender panel there to help see and work on the vacuum junction. Here is the culprit fully pulled out: I tested it by capping the end after I removed it from the back of the manifold, it held "NO" vacuum at all- I mean I could blow through it and inhale through the line even though it was capped off on one end!
I had to jack up the front end of the Vette and turn the wheel all the way to the left, so I could remove the panel to access the area by the PCM and Vacuum junction One Way Check Valve.
You "WILL" need to take all the 7mm nuts off the panel (The ones underneath too) AND the last one for the fender on the bottom furthest toward the rear of the Vette right next to the door!
This is because you will need to pull a little on the fender panel there to help see and work on the vacuum junction. Here is the culprit fully pulled out: I tested it by capping the end after I removed it from the back of the manifold, it held "NO" vacuum at all- I mean I could blow through it and inhale through the line even though it was capped off on one end!Damaged area:
It is not hard to get your hand behind the manifold with the Valve cover/coil covers off , plus make sure you unclip the MAP sensor it makes it a little easier too get your hand on the vacuum line- I pulled the rubber end of the line off the fitting in the back (there are only two fittings on the back for vacuum) One for the Brake BOOSTER and one for the HVAC Unit
After it was all traced out and I found the end in the fender well - It ran into a oneway check valve: (Pic) The line on the bottom comes from the manifold and the other two - One goes to the canister right above and the other goes into the Vette's Cabin to the HVAC vacuum block.
With it pulled off:
The bottom goes to the manifold (vacuum supply) the one off the side goes to the Canister above and the one in the middle (top) goes into the cabin area.
The bottom goes to the manifold (vacuum supply) the one off the side goes to the Canister above and the one in the middle (top) goes into the cabin area.
Next I re-routed the new vacuum line to the unit using 3/16" fuel/vacuum line: Plugged it into the Manifold and routed it behind the battery down to the canister area-
All tucked in:
Remember to re-plug in the MAP sensor
Remember to re-plug in the MAP sensor
Next I went to the fender area and tested "ALL" the lines off the One-Way Vacuum Check Valve (Using my mighty Vac): Tested to 20 PSI, the only one that did not hold was the direct line to the manifold:
I went ahead and replaced the small 90* vacuum line to the canister for a just in case since it was easy enough(You never know) :
Now After that was done I went into the Vette and removed the floor mat, the panel covering the BCM (Computer) and the upper kick panel - now make sure you pop the foot well light out of the upper panel so you can remove the whole thing and have a free open area to work (YEAH! Like there is a lot of room anyway - all twisted on my back crunched in that little area- Stinking crazy! )
Here is a shot of the line coming into the cabin area from the fender: They are kind of a hard to see but they are the two (One from the manifold and one from the check valve to the cabin) there in the back ground right above the PCM:
Now I tested the line from the fender to the cabin, here is a shot inside the Vette - The Black plastic line from the One-Way Check Valve couples into a "PURPLE" Line : As seen in pictures
Black plastic supply line: Seen at finger point
Black plastic supply line: Seen at finger point
Pulled down a little to see the coupler: Black into Purple
A few pics of all the pretty colored vacuum lines from the vacuum block: (And to think I was getting no vacuum to this bad boy 
)
)Next I pulled the Black to Purple Couple apart for testing and capped it off: Held very good at 20 PSI of vacuum for a sustained period of time:
I also tested the vacuum block and it held too. I was glad the supply line was good because I did not want to punch a hole in the firewall to install a 3/16" vacuum line, So I was able to use the factory one.Since it was good at this point I buttoned up the inside and put it all back together - even the floor mat - no really I did! Now back outside to the fender area where I re-assembled the One-Way Check Valve: Here are a few pics installed
At this point you can put everything back to factory - the fender screw and the panel screws and snug them all down - Lower the Vette back on the ground and make sure nothing was left off and no extra parts! AGAIN: Make sure you clipped the MAP sensor wire back in - because you needed to pull it off for easy access to the vacuum fitting on the back of the manifold - You did put it back on right!
Well now it is time for the test: Fire up - Turn on AC - Try different Modes - ALL WORKS GREAT - It's a cold party in here
A special THANKS to Matthew madmatt9471 on the Corvette Forum for sharing this Write-up with his fellow Corvette Owners
03-26-2012, 09:58 AM
#10
Anyone have any suggestions if I'm getting hot air out of the passenger vents but cold out of the drivers? I can change where the air is directed. Should I start with a freon level test?
03-26-2012, 10:40 AM
#11
Burning Brakes
Blackdak, first thing is to check for codes on your DIC, looking at the HVAC area. Its either the actuator or low freon level, but start with the codes first.
Should have read this closer, its porbably your actuator on the passenger side, but again, check for codes first.
Should have read this closer, its porbably your actuator on the passenger side, but again, check for codes first.
Last edited by dmarkshark; 03-26-2012 at 06:12 PM.
03-26-2012, 02:42 PM
#12
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I have the same issue with a 01 Z06. I will try the battery tonight as mentioned by corvettebob, and will check the fuses. Dealer wanted $1100 to "get into" the dash and see if it is the vent doors opening of closing. I can hear them move when I switch too and from defrost and when I bring in outside air. Driver side just blows hot and passenger side blows cold.
03-31-2012, 02:08 PM
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Added INFO to an earlier post. Upon further review, here are the symptoms with my HVAC right now. Driver side set on 61 degrees & passenger side set to match the driver (**** pointing straight up):
1. The passenger side gets significantly cooler than the driver side. The amount of air flow is equal driver and passenger
2. On the electronic display, the only 2 air modes I can get are blowing air to both the upper vents & foot vents (2 arrows on the display); and blowing air to both upper & foot vents, along with the defrost (2 arrows on the display, plus the DEFOG symbol).
3. I disconnected fuze 27 in an attempt to reset, but nothing happened.
Thanks
1. The passenger side gets significantly cooler than the driver side. The amount of air flow is equal driver and passenger
2. On the electronic display, the only 2 air modes I can get are blowing air to both the upper vents & foot vents (2 arrows on the display); and blowing air to both upper & foot vents, along with the defrost (2 arrows on the display, plus the DEFOG symbol).
3. I disconnected fuze 27 in an attempt to reset, but nothing happened.
Thanks
04-02-2012, 11:22 AM
#16
Melting Slicks
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Removing the fuse rarely works....
You will need a Pro to check if your low on freon, or a refrigeration class along with gauges and refrigerant recovery equipment.
04-02-2012, 11:34 AM
#17
Team Owner
Freon
vacuum
actuator gear
thats about the only things it can be
freon low means you have a leak
vacuum...loose or broken hose
actuator..they can be reset by a TECH II if other methods fail or you can buy a new head unit from 01 and up that has a logic built in that resets them thats what I did when I decided I couldn't get my hand in there to remove the actuator and I didn't want to take my entire dash apart
good luck...I know how much this sucks
vacuum
actuator gear
thats about the only things it can be
freon low means you have a leak
vacuum...loose or broken hose
actuator..they can be reset by a TECH II if other methods fail or you can buy a new head unit from 01 and up that has a logic built in that resets them thats what I did when I decided I couldn't get my hand in there to remove the actuator and I didn't want to take my entire dash apart
good luck...I know how much this sucks
