Just got my car back from having a new engine installed.

When I cranked up the AC for the 100 degree plus weather we're having.... I get ice cold from the drivers vents...but smoking heat (not outside air heat) from the two passenger vents. The dual control on the passenger is set to the coolest setting.

What may be causing the problem? I didn't have this before the car went for the engine replacement...but stuff does fail so it may not be related..just wanted to put it out there for toubleshooting. Head unit? Something stuck?

 

Don't assume the system is fully charged because only one side is cool.
Do a freon check and make sure you aren't low.

 

It's not two separate systems so I don't see the logic.....

 

Could be the actuator. Do you have any HVAC codes?? Try resetting / reindexing the actuators.

I don't understand it either, but have heard it could be the charge. Here's a charging 101 thread.

http://forums.corvetteforum.com/c5-g...-ac-101-a.html

 

OK, then. How about posting the HVAC codes,then. If there are none, you might want to at least TRY Jim's solution or you can pull fuse #27 in footwell, replace it and see if that works.

 

The logic is simple... just misapplied in this case.

The "Dual Climate Control" found in the C5 consists of a digital HVAC head unit, a single 'hot deck' and a single 'cold' deck, various dampers that are controlled by the head unit, and sensors that provide feedback to the head unit for actuator position, temperature, etc...

The 'hot deck' is your heater core. The 'cold deck' is your AC evaporator core. The actuators are used to control individual dampers (driver or passenger side) which direct either hot or cold airflow to the intended discharge point(s). (Defrost, vent, floor.)

The evaporator is indeed one single system, so one would think that 'maximum cold deck' temperatures coming out of the passenger side would be equal to the drivers side. In a perfect world, on paper, or in the lab, that would be true.

Unfortunately, that's not reality.

The freon is released into the evaporator starting with the coils closest to the passenger side of the car. As air passes between the evaporator fins, heat is absorbed into the freon as it travels through the evaporator coils and continues towards the drivers side of the coils. When your freon charge is sufficient, there isn't much difference between the drivers side and passenger side temperatures of the vehicle... but there is SOME difference due to heat absorbtion.

In the event of a low charge, the freon that is remaining in the system cannot absorb the heat from the cabin properly. The result is a (seemingly) cold passenger side, and a warm (or hot) drivers side. I say 'seemingly' because in 100 degree heat, 80 degree air from the passenger duct 'feels' cooler... but unless you are making temperature measurements with a thermometer, it's subjective.

Anyway, this situation is a common issue on the C5, but in your case it was incorrectly applied. A cold drivers side and a hot passenger side indicates a failure of the actuator that controls the hot/cold deck, a bad position sensor within the actuator, a bad HVAC head unit, or another issue entirely. (Loose connection, bad ground, etc...)

Hope this helps.

Mark

 

FASTHOTROD - thanks for the explaination.


I pulled the fuse and did the recycle. I disconnected the battery and tryed the recycle. No luck.

I am getting an HVAC code B0446 (Right actuator out of range).

What's next - replace the actuator - or is there another recycle I can do

 

you could try removing the actuator and reindexing the gears. Theres a post on here recently that walks you through it. Search for actuator indexing or along those lines.

edit: here ya go...

http://forums.corvetteforum.com/c5-t...actuators.html