Air Conditioning

[MarxModified]

Not sure if this is the right thread. My 07 LMM is having some AC issues. Every once in a while it won’t blow cold air when I start the truck up. It’s not blowing hot air, it’s still cool but not ice cold. It will take about 20 minutes for it to start blowing ice cold. There’s other times when I turn the truck on and it immediately starts blowing ice cold. I tried to recharge the refrigerant but the gauge on the bottle read that it was ok. Any idea what it could be?
The heat in the winter is also kinda slow to start blowing hot and I figured that’s because it takes so long to warm the engine up. At least I thought that until my dad got his 19 L5P and it warms up real quick and so does my work truck 13 LML(which I figured single cab and cloth would be easier to warm).
Any help would be appreciated

 

[Chevy1925]

LML and up got an electric grid heater in the hvac to aid in heating when these trucks are first started in the cold mornings.

for the a/c, try an hvac relearn

1. Clear all DTCs.
2. Place the ignition switch to the OFF position
3. Remove the HVAC/ECAS fuse for a minimum of 10 seconds.
4. Install the HVAC/ECAS fuse.
5. Start the vehicle.
6. Wait 40 seconds for the HVAC control module to self-calibrate.
7. Verify that no DTCs have set as current DTCs.

if that dont work, you need to have the system checked with actual gauges on it. the single low pressure gauge on the cheap cans from auto stores aint enough. overfilling it can cause its own issues. could be a slightly low system or could be a fan clutch thats not working correctly. lots it could be.

 

[02greysixer]

Yep, a bad fan clutch will act similar. I'd say maybe 1 in 10 times I start my lb7 the ac will not be cold and will short cycle when stopped. Running down the road at speed it cools off and seems like once it builds a little heat the fan starts pulling again and it works at idle. Fan clutch is dying and occasionally just lets the fan free spin on start up.

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