AC Intermittently Works (HVAC thinks it's in front defrost mode)

Discussion on Air Conditioning/Heat & electronic controls for the same, radiators/fans/engine cooling and related items.
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counterattack
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Joined: Fri Mar 04, 2022 7:32 pm

AC Intermittently Works (HVAC thinks it's in front defrost mode)

Post by counterattack »

Hello everyone, I'm new the the Caprice platform and the forum. I have a 2013 9C1 with 30k miles. It's been running great, however, this past week the AC started giving me issues. The fans would work and what not, however, it wouldn't blow cold. When I turn the temp up it gets much hotter and the passenger side vents are warmer than the drivers side when set to C. As I played around with the settings it gave me an error message saying I could not go into recirculation while in front defrost mode (which I was not). All the while the radiator fan I believe is howling.

I disconnect the battery that night go for a drive and the error message is gone. However the next day the same issue is back.

I was reading on some older posts that over or under refrigerant can cause issues but this kinda seems like an HVAC issue? Or a compressor issue? I'm just trying to figure this out as it's going to get hot soon down here in Southern California.

Thanks everyone
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elc32955
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Re: AC Intermittently Works (HVAC thinks it's in front defrost mode)

Post by elc32955 »

OK folks, let's give this new member some help here... I only have a 2011 FSM and didn't have to troubleshoot the AC on my old car, so I'm not a good go-to source on this one.

Thanks
Eric
System Manager and your tour guide for the day. 2015 Caprice w/LFX, former NC DPS staff car. Partial hybrid G8/SS/Camaro SS interior mods, SS MyLink radio upgrade, 2016 Camaro V6 rims, GMPP Malibu chrome exhaust tips, otherwise bone stock for now.
Sanford
Posts: 356
Joined: Mon Dec 12, 2016 9:38 pm
Location: Texas Gulf Coast

Re: AC Intermittently Works (HVAC thinks it's in front defrost mode)

Post by Sanford »

Need to start with the basics. Is the compressor clutch engaged? Do you have a set of AC gauges so you can check pressures? The most common problem with mine have been leaking high pressure charging ports. With a cold start, both fans should run on low speed with the AC on. They will kick up to high speed if the head pressure gets high enough, which is probably around 250 psi.
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