Ac Question For 08 Ltz Chevy 2500hd

cfeiring · August 4, 2008

Hello

I have a question for the GM tech folks.

First I did RTFM/RTFB.

Now here is the situation / question I have a new 2008 /chevy 2500 LTZ Dmax crewcab, When I run the HVAC system in the manual mode (auto is turned off / not lighted) and the AC-Snowflake is (not lighted / turned off) the system will still blow cold air just as if the AC system was on.

Is the system smart enough to know that cold air is wanted and does the compresser still running?

Is this do to the tempreture setting in the system vs outside tempreture? - It is summer so it is about 90 dg F or higher here in VA have the inside temp set to 70F.

Is there any benefit running this way vs Auto ?(talking about drag by compresser and resulting reduced MPG).

I discovered this fact buy trying to cool of the componets just prior to parking after using the AC. I used to do this in my old truck to try and reduce the heat load when parking in the heat of summer.

Looking forward to your collective wisdom and information.

minibike132 · August 4, 2008

First I did RTFM/RTFB

I'm sure I should know but what is this.

As far as vehicle specific for 08 I don't really know because I have not paid attention in one. The way the circuit description is worded it looks like the A/C should turn off and that makes the most sense. Are you sure the compressor is still on? Is it in Recirc mode, in most trucks I've driven once the cab is cold if your in Recirc it can keep quite cold for along time. Pop the hood and make sure the compressor is on if so take it to your dealer, if it is normal they will be able to show you a like model doing the same thing, if not they can fix you up. I would lay good money on it just recirculating cold air though.

cfeiring · August 6, 2008

Thank you for your response.

Sorry for the delay I work shift work and on my days I work do not have time to read/post.

RTFM / RTFB --- Read the free book / manual ---- sorry its a computer slang term .... can also be not so family friendly in terminolgy

usually the first step in determining problem/solution....most folks do not bother to read the documents provided with techinical equipment / software and in my experince a lot of problems can be resolved with a few mins and pages read of documentation to resolve a "problem". I would assume that it would be similar with a car / truck avg consumer / user.

I will have to pop the hood to see what is going on. But man, its a jungle in there am afraid of what might jump out at me.

I have to get a step stool just to check the fluids in this beast.

But I have a 22 mile ride to work and will turn on the system as noted above (snow flake off but on recirc on) and it will blow cold air the entire trip so not sure what is going on and yes you were correct I do use the recirculate mode as it keeps it cooler and less humid and trying to improve mileage and also as I stated I drive the last mile or so with what I think the commpressor off to let the AC release all the remaining heat while moving to keep the under engine temps as cool as posible in the hot VA sun as it first shuts down (engine).

I thank you for your time and will do the testing and follow up here and at dealer if needed.

I do not think it is a real problem untill it is winter here, and then most of the time I would just want the natural outside temp air to come in vs the heat and or AC as I do prefer to be a bit cold - keeps me awake as I work at night and sleep during the day most of the time.

bossier62guy · August 7, 2008

Thank you for your response.
Sorry for the delay I work shift work and on my days I work do not have time to read/post.

RTFM / RTFB --- Read the free book / manual ---- sorry its a computer slang term .... can also be not so family friendly in terminolgy

usually the first step in determining problem/solution....most folks do not bother to read the documents provided with techinical equipment / software and in my experince a lot of problems can be resolved with a few mins and pages read of documentation to resolve a "problem". I would assume that it would be similar with a car / truck avg consumer / user.

I will have to pop the hood to see what is going on. But man, its a jungle in there am afraid of what might jump out at me.

I have to get a step stool just to check the fluids in this beast.

But I have a 22 mile ride to work and will turn on the system as noted above (snow flake off but on recirc on) and it will blow cold air the entire trip so not sure what is going on and yes you were correct I do use the recirculate mode as it keeps it cooler and less humid and trying to improve mileage and also as I stated I drive the last mile or so with what I think the commpressor off to let the AC release all the remaining heat while moving to keep the under engine temps as cool as posible in the hot VA sun as it first shuts down (engine).

I thank you for your time and will do the testing and follow up here and at dealer if needed.

I do not think it is a real problem untill it is winter here, and then most of the time I would just want the natural outside temp air to come in vs the heat and or AC as I do prefer to be a bit cold - keeps me awake as I work at night and sleep during the day most of the time.

This subject has been covered a few times in the past and the general consensus is that as long as the system remains in the RECIRC mode the compressor is still running.