HVAC Mystery

[Junkman]

Okay Paul and gang, I have a good one.

I was experiencing the common issue with the driver's side blowing warm while the passenger's side was blowing cold. This happened after having the battery disconnected for a week or so while I was repairing my wreck. So I broke out my service manual, pulled my codes and looked them up. The first thing that I tried doing was recalibrating the actuators by pulling fuse 27 for a minute or more. No change. I even tried disconnecting the battery. Still no change. I then hooked up the necessary hardware to verify that my freon levels were correct. All levels were where they should be.

Using a scan tool the next day, I commanded the driver's side actuator open and closed and it appeared to operate normally. However, the driver's side air never really got cold as the passenger's side. I had a brain fart and forgot my service manual so I didn't know exactly what values to look for.

Due to my codes (B0338 & B0363), I decided to pull the driver's side actuator and see if it had any physical damage. It looked fine and appeared to be working. I have an extra HVAC unit that I know is good so I plugged it up just to see what would happen. No change. Finally, I MANUALLY closed the actuator door (I actually heard it shut loud and clear). The air is still not as cold as it should be.

At this point, I'm kinda out of ideas. My next step is to get the scan tool and follow the manual's trouble-shooting flow chart but before I do that, I figured that I would bounce this off you guys. I gotta get this wrapped up so that I can attend Bloomington Gold next weekend!

One thing to note. With the wreck that I had, I had to replace the inner fender on the passenger's side. I understand that there is a vacuum line to the HVAC over on that side of the car. Could I have maybe knocked it off or crunched it during the repair? If it has anything to do with this, I'll pull the tire and go hunting for it.

Another note, all my vents change when they are supposed to and the car blows plenty of heat. Also, I have the driver's side actuator out of the car so that's probably why it's throwing the B0363 code.

A.J.

[c4c5specialist]

HI there,

You should see between 5 and 250 counts on the actuator values.

Anything other than that, vacuum will not have anything to do with these codes setting.

If your actuator value is at 0, there is an issue.

Allthebest, c4c5

[Junkman]

Here's where I'm confused. I removed the actuator and manually closed the door. While holding the door closed, lukewarm air still continued to blow through the driver's side vents. I worked the door both way to make sure that I had it in the right position. Am I missing something in my logic in thinking that I was performing the same function that the actuator door performs? This is why I was thinking that the actuator was not bad.

[LLC5]

Originally Posted by Junkman

Here's where I'm confused. I removed the actuator and manually closed the door. While holding the door closed, lukewarm air still continued to blow through the driver's side vents. I worked the door both way to make sure that I had it in the right position. Am I missing something in my logic in thinking that I was performing the same function that the actuator door performs? This is why I was thinking that the actuator was not bad.

If your blend doors and actuators are functioning properly, I have seen a low freon charge cause this condition, but only in auto temp and dual climate zone controlled a/c vehicles. Good luck with it.

[Junkman]

Originally Posted by LLC5

If your blend doors and actuators are functioning properly, I have seen a low freon charge cause this condition, but only in auto temp and dual climate zone controlled a/c vehicles. Good luck with it.

That's exactly what I was thinking and is also why I checked that first. I have also seen that same condition before.

[ToolGuy]

Originally Posted by LLC5

If your blend doors and actuators are functioning properly, I have seen a low freon charge cause this condition, but only in auto temp and dual climate zone controlled a/c vehicles. Good luck with it.

My Grand Prix dual zone elec climate does the same. If the drivers side is like 4-6 deg warmer then the passenger side, its a low charge and needs to be topped off.

[Junkman]

Originally Posted by ToolGuy

My Grand Prix dual zone elec climate does the same. If the drivers side is like 4-6 deg warmer then the passenger side, its a low charge and needs to be topped off.

I'm thinking the same things and am on my way to the dealer. Even though my reading say I'm good, I'm going for a second opinion.

[LLC5]

Originally Posted by Junkman

I'm thinking the same things and am on my way to the dealer. Even though my reading say I'm good, I'm going for a second opinion.

Make sure that when they evacuate the system, they measure how much freon was taken out so you will know for sure if it was low.

[Junkman]

Originally Posted by LLC5

Make sure that when they evacuate the system, they measure how much freon was taken out so you will know for sure if it was low.

And that's exactly what I did.

Luckily, the only guy I allow to work on my Vette at the dealership is a World Class Certified GM Technician and he and I talk in-depth before any work is actually done. The shop managers just walk away when we get together because they know that I won't allow anything to be done unless I have a full understanding of what is to be done. This tech takes the time to explain what he is going to do and the logic behind his diagnosis. Understanding his logic is the most important part of the repair for me because I have to justify the cost of the repair when I could be doing it myself. Lucky for him, I had done all the guess work and narrowed it down to two things:

• Broken vent door.
• Low freon.

The broken door was a really long shot because that is not a common failure with this model car and the redesign of the actuators in the 2001 and later models pretty much eliminated that from happening. Thus, I went for the evacuate and refill. When he did that, the amount of freon in the system was only .4lbs (1.5 is spec). So he charged the system and BAM... I was cold on the way home.

I have a full understanding of what fixed my problem. What I don't understand is how the compressor was able to kick on and run undisturbed with such a small amount of freon in the system? From my understanding of all AC systems, they all have fail safes built in that will cut off the compressor if the freon is too low, or the compressor will constantly kick on and off if the system is too low. Could it be that .4lbs is NOT too low? That seems very low to me.

The last bummer is the fact that I have a leak. Most likely it's going to be the compressor because that is the only moving part in the system. The leak is extremely small and I had them inject some dye into the system so that we can locate the leak. At least I'm working again and thus,

Bloomington Gold, here I come!

[ToolGuy]

Originally Posted by Junkman

The last bummer is the fact that I have a leak. Most likely it's going to be the compressor because that is the only moving part in the system. The leak is extremely small and I had them inject some dye into the system so that we can locate the leak.

Nah, you can't say that and be 100% true. Sure its the only moving part in the system but there are many joints/connections with seals and O-rings in the system. Any can be at fault. The dye will reveal the issue.

In reading this again, did you discharge the HVAC system from the wreck? If so, did you pull a vacuum on the system before recharging? If recharging at home, did you follow the R134A chart for adding freon in relation to outside temps and humidity? These steps are are very critical in charging an HVAC system back up.

I just ask because you said you had a extra HVAC unit, implying the system was discharged.