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Important! 01 C5 passenger A/C blend door problems

jackel

Member
Joined
Jan 22, 2012
Messages
15
Location
Texas
Corvette
2001 Coupe, Torch Red
Hello,

My 01 passenger side blows cold air fine but the temp can't be regulated by the passenger. No matter if the knob is set to hot, it still blows cold and winter is here and freezing on that passenger side. I need help to locate the passenger blend door actuator so I can check it for operation.

Thanks for the help.
 

LT4man

Well-known member
Joined
Jun 25, 2003
Messages
2,214
Location
Chicago
Corvette
96 Collectors Edition LT4
I believe I have read some threads here speaking to your exact issue.

This seems to be a very common problem on the C5s.

XLR8 had some personal experience with this.

If no one speaks up, please try the search tool.
 

Toms007

Moderator
Joined
Sep 24, 2004
Messages
6,338
Location
Southwest Kansas
Corvette
2007 Atomic Orange Coupe
Jackel, have you tried recalibrating the HVAC? Here's a post from another member. From this thread http://www.corvetteactioncenter.com.../129116-help-my-97-blowing-hot-cold-once.html

Originally Posted by Junkman2008
Allow me to post a correction in the fix for recalibrating the HVAC. What the OP posted as the fix is slightly off, although it worked for him. The correct procedure is:

Re-Calibrating Actuators

Use the following steps to perform the calibration update:

1. Turn OFF the ignition.

2. Remove the battery positive voltage circuit fuse of the HVAC Control Module (fuse 27, located in the passenger's side floorboard by the BCM).

3. Wait 60 seconds.

Important
The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.


4. Install the fuse.


There is no need to disconn
 

jackel

Member
Joined
Jan 22, 2012
Messages
15
Location
Texas
Corvette
2001 Coupe, Torch Red
I appreciate the help... Well I tried that fix and it didn't work, my temp controller controls all the vents temp but the passenger side actuator I believe must be defective. I found the location of the actuator and there is no way to check voltage without removing the dash completely. I guess I have my work cut out for me.

Thanks
 
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Junkman2008

Well-known member
Joined
Aug 11, 2007
Messages
560
Location
Kentucky
Corvette
2001 Navy Blue Metallic Coupe
I appreciate the help... Well I tried that fix and it didn't work, my temp controller controls all the vents temp but the passenger side actuator I believe must be defective. I found the location of the actuator and there is no way to check voltage without removing the dash completely. I guess I have my work cut out for me.

Thanks

I have directed so many guys on how to fix this problem that my fingers are blue from typing. But here I go again.

The secret to solving this problem is proper trouble-shooting. You cannot fix this problem until you know some variables. Instead of typing the entire procedure out again, I'll point you in the right direction. Once you complete the initial information gathering stage, then I'll explain how to resolve your issue.

Step 1. Attempt the recalibration of the HVAC. - You have completed this step and the problem still exist.

Step 2. Perform a evacuation and recovery of your R-134a (freon to you old guys). - What this will do is tell you EXACTLY how much R-134a is in your system. If there is too much or too little R-134a, your system will do weird things. Your year car should have exactly 0.68 kg (1.50 lb) of R-134a in it. You'll have to go to some place that has a ACR 2000 Air Conditioning Service Center machine (or similar), capable of doing this and getting you the readings that you need to know. Find a mom and pop shop that can do this. The dealer will rip you a new one on the cost. A mom and pop shop will charge you around $50 if they don't have to add any R-134a.

If they do have to add R-134a, then you have a leak. When they refill the system, make sure that they also add some green dye to the system so that you can locate the leak. Without the dye, you will never find the leak. Once you locate the leak (if any), then I can direct you on how to fix the leak.

Note: You say that the passenger's side is blowing only cold air. This is highly unusual for a R-134a problem because on a automobile HVAC system, the air usually defaults to heat if there is a refrigerant problem. The reason cars are designed to do this is because you can drive a car year round without AC, but you can't drive a car in cold climates without heat (you won't be able to defrost the windows for one). So the fact that your vent always blows cold makes me think that you have an actuator problem on the passenger's side. The thing is, the actuators in the 2001-2004's are not a common failure part. They did have an issue with the earlier models but not the ones in your car. Since the dash pad has to come off the car in order to replace the passenger's side actuator and is a fair amount of work (not so for the driver's side), you don't want to go there unless you have to. That's why you want to verify the refrigerant level before pulling the dash pad.

So your next step is to find out what your R-134a level is. Then we will take it from there. One more side note. On the dual climate control HVAC units, the passenger's side has their own temperature knob. Although it allows you to somewhat control the temps on that side of the car, it will not be a significant amount of change from what the driver's side is blowing. Some people are under the misconception that you can blow cold air out the driver's side and heat out the passenger's side at the same time. The only time that is possible is when there is a problem with your HVAC system.
 

jackel

Member
Joined
Jan 22, 2012
Messages
15
Location
Texas
Corvette
2001 Coupe, Torch Red
The A/C has been functioning well and blows very cold, everything works except the passenger side temp controller. If I like my side to blow at 65 and the passenger wants it to be warmer, it should allow that side to warm or cool off. I have had Chevy trucks with the same HVAC configuration and the passenger side discharge air would be 10˚ warmer. Now, the passenger side blows whatever temp I have the drivers side set. I appreciate your help.
 

Junkman2008

Well-known member
Joined
Aug 11, 2007
Messages
560
Location
Kentucky
Corvette
2001 Navy Blue Metallic Coupe
I have never seen a C5's HVAC blow with that much of a degree of difference. I know mine doesn't for sure. However, the temperature being blown is determined by the signal being sent to the actuator and the actuator adjusting the doors. That puts the problem being in either head unit itself, the actuator or the wires in between. If you can get both sides to blow very hot AND very cold, I'm going to say that you have no problem. I would say it is what it is.
 

Delta98C5

Member
Joined
Oct 4, 2019
Messages
20
Location
Jefferson Parish, LA
Corvette
stock 98 C5 pewter 145K miles
Jackel, have you tried recalibrating the HVAC? Here's a post from another member. From this thread HELP! My 97 blowing hot and cold at once!

Originally Posted by Junkman2008
Allow me to post a correction in the fix for recalibrating the HVAC. What the OP posted as the fix is slightly off, although it worked for him. The correct procedure is:

Re-Calibrating Actuators

Use the following steps to perform the calibration update:

1. Turn OFF the ignition.

2. Remove the battery positive voltage circuit fuse of the HVAC Control Module (fuse 27, located in the passenger's side floorboard by the BCM).

3. Wait 60 seconds.

Important
The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.


4. Install the fuse.


There is no need to disconn
This worked for me ! I went through and cleared codes first . Two of them I could not clear but as soon as I did I could hear something in the center of the dash moving and creaking . Then I pulled the #27 fuse for a while , reinstalled , and then started the car . It was blowing cold again. Down here in S Louisiana the weather is always highly variable this time of year. I had done a heater bypass for the summer but I reversed it last month and this problem starts up again . I know it'll come back and that I'll have to address the actuator problem itself at some point . I've been looking at some heater bypass valves for various cars online and I'm not sure how that will work but I saw one for the last generation GTO that is vacuum operated . My thought was that I could make it manual somehow. I was thinking of going this route because in the hot months , even when the actuators are behaving , I've noticed the car just feels hotter when I get back into it. Also the windshield seems to fog up as well . This occurs after I drive it somewhere and then get back into it to leave . I know the first reaction is going to be that I have a coolant leak but I don't . I never have to add coolant to it and I check it before I drive it . The car is 22 years old and I don't use it that much so I always pop the hood before I take it out . I am fully aware that the entire dash should probably be taken down and everything checked and all of the actuators replaced and I may do that at some point but it's nice to buy some time with an easy procedure like this . Thanks again for this advice. I'll see how it goes on the next drive .
 
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