A/c problem

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Jul 18, 2021 | 03:32 PM

C5.dro

Thread Starter

Instructor

Joined: Apr 2020

Posts: 233

Likes: 14

From: Dallas Tx

A/c problem

So here’s a update on my ac problem that I can’t seem to figure out. When I turn the car on and ac Is on and on full cold it just blows hot air but as soon as I start to drive the cold air come on and stays on. Any ideas on what I should check or replace? I already checked all the a/c lines and none of them have been disconnected,cracked,or anything like that. Doesn’t throw any codes

Jul 18, 2021 | 05:32 PM

purrvert

Racer

Joined: Aug 2004

Posts: 438

Likes: 15

From: satellite beach fl

Check your vacuum lines.

Jul 18, 2021 | 05:51 PM

bonesbrakr

Burning Brakes

Joined: Aug 2011

Posts: 827

Likes: 286

Check your fans. No air across the condenser = no cold AC

Jul 18, 2021 | 06:40 PM

C5.dro

Thread Starter

Instructor

Joined: Apr 2020

Posts: 233

Likes: 14

From: Dallas Tx

Quote:

Originally Posted by bonesbrakr

Check your fans. No air across the condenser = no cold AC

I changed my cooling fans aswell because one of them wasn’t working bought it used from a corvette store maybe it’s faulty? Car doesn’t overheat though and before with my original cooling fan it overheated because one of the 2 fans wasn’t working. Car blows cold air when I start driving so I’m guessing MAYBE one of the fans is set to turn on at a high temp lol which is why maybe I don’t get cold air until I start driving? Or does that not make sense lol

Jul 18, 2021 | 07:49 PM

bookyoh

Pro

Joined: Dec 2014

Posts: 681

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From: Cincinnati Ohio

Perhaps answers to a few a questions can narrow this dow.
1. When you say it blows hot, do you actually mean hot like heated air or just a little warmer than the outside air temperature?
2. Is your compressor running at idle?
3. With the a/c on, are both fans running at idle and are they pulling air into the engine compartment?
4. If you start the with the a/c off, let it idle for a few seconds, and then turn on your a/c, do you get cool air for some seconds or minutes before it stops cooling?
5. Does the air continue to blow through the upper vents wheter you are at idle or driving?

Jul 18, 2021 | 08:15 PM

Smoken1

Joined: Apr 2013

Posts: 5,023

Likes: 1,150

From: Oregon

St. Jude Donor '14-'15-'16-'17-'18-'19-'20-'21-'22-'23

Quote:

Originally Posted by C5.dro

Both fans are commanded on at the same time
Factory temp settings are low speed on at 226 degrees and off at 219 degrees. High speed on at 235 degrees and revert to low speed at 226 degrees. Both fans run at low speed and high speed and fans are commanded off by the PCM when the vehicle speed exceeds 35mph.

You can force low speed operation at 185 degrees by turning on the AC. High speed operation with AC on is still 235 degrees.

Jul 18, 2021 | 11:37 PM

purrvert

Racer

Joined: Aug 2004

Posts: 438

Likes: 15

From: satellite beach fl

When A/C is on fan control is prioritized by a/c pressure. Both fans at low speed on at 219 PSI, off at 180 PSI. Both fans at high speed on at 255 PSI, off at 219 PSI. Clutch disengages at 410 PSI. These numbers are from my 2000, yours will be very similar.

Jul 19, 2021 | 09:39 AM

grinder11

Race Director

Joined: Oct 2004

Posts: 12,859

Likes: 4,658

Quote:

Originally Posted by C5.dro

Has your car ever been tuned? Stock or modded? I ask because my car did, and does still, the same thing. My car is modded and tuned. After a lot of troubleshooting, and wasted time and $$, I discovered the tuner set the A/C so when the car was at a stop, the A/C compressor would disengage!! This was done to obtain a better idle with the performance cam, and done without my knowledge, or permission. Figured this out with a lot of help from C5Diag, and someone, can't remember who (sorry guy!) in the scan/tune section. If you have a stock tune, please disregard. Went into detail to try and inform you, and others, of something that could be an issue, and something that cost me some serious (hundreds!) $$$!!