AC button blinking and no AC

[lfootmatt]

Greetings,

2008 H3 Alpha, 125,000 ish miles.

AC light blinks 3 times then goes out and no AC.

I’ve checked the likely culprits. Pressures look good as best I can tell with a crappy top off bottle.

I’m leaning toward the temp sensor in the evaporator core.

Does anyone have any experience or advice for this one?

Thanks!

Matt

 

[Happy Hummer]

Typically indicates a system fault, with common causes including low refrigerant, a bad compressor, electrical issues like a faulty control module or wiring, etc. The blinking light tells the computer to disengage the compressor.

 

[HummerMan7]

From what I know three blinks usually mean the HVAC sees a fault and won’t let the compressor turn on, start with real manifold gauges (not a top-off can), check the A/C fuse/relay, and see if the clutch is getting a command. If charge and power are good, look at the pressure transducer and evap temp sensor next, and pull HVAC codes with a scan tool to confirm before buying parts.

 

[lfootmatt]

Thanks for the info!

One more thing, the entire AC system was replaced 3 years ago.

Ran incredibly cold in spite of being in Arizona in a hot running Alpha.

I’ll have my son get it scanned. I don’t think my cheesy cheap scan tool will see the AC system.

Thx!

 

[NMH3]

This will also happen if you press the AC button when the HVAC fan is in the "off" position.