06 Silverado A/C clutch not engaging.

[Jimmy284]

2006 Silverado 5.3 flex fuel. I went to turn on my a/c and it just blows hot. I took it to the shop and they said all fuses and relays were good and sensors seem to be ok but the hvac control module isn't sending a signal to the clutch to turn on. I replaced to clutch cycle switch and I replaced the dual climate control. I've done numerous resets with key turns or fuse pulling and nothing seems to work! Any help would be appreciated!

[Jsdirt]

If it were mine, and you were 100% sure it's just the electronics not working, I'd just power the low-pressure cutoff switch (cycling switch) by a toggle switch, and sell the new control on eBay. Eliminates all the electronic crap, and gets you some cool air very easily. Throw the switch, and the compressor will kick on until the switch begins to cycle it. Just turn on the blower fan to the desired speed and vent, and you're good to go. Would just have to remember to kick that switch off in cooler weather, or anytime you don't want A/C.

 

Sounds like the electronics are the only thing keeping it from working ... unless it's just low on 134a - no power will get to the clutch switch in that case.

 

Did the shop tell you the pressures? Did they even check?

[kstruckcountry]

Take it to a shop that actually knows what they're doing.

[Jsdirt]

There shouldn't be more than one control unit for the system. We all know how GM loves to save a buck - I can't see them having 2 modules run the system.

 

I wonder if disconnecting the battery overnight, or for a half hour, will suddenly make the unit wake up? Worth a shot anyway. Or, maybe it needs to be flashed in with a scan tool. Never know these days.

 

The engineering on some of these systems is baffling ...

[Jimmy284]

The shop hooked it to their computer and said the freon was good as far as full and pressure was right. They could use their computer to turn the compressor on and said the hvac control module has two wires that control the clutch and the signal isn't getting to the clutch to turn on. I replace the dual climate control thinking it was the module they were talking about and nothing changed. I also replaced the fuses and relays even tho they said they were good. Also replaced the clutch cycle switch just in case but none of this worked. Is their another hvac control module in the dash? I'm just trying to do it myself and save hundreds in labor.

Thanks for the replies!

[Jsdirt]

Ahh, now I get a clearer picture. A wiring diagram would help you out tremendously. Could be a wiring issue (if you're lucky), or some other electronic wiz-bang wonder GM stuffed in there ...

[Jimmy284]

Yeah when I look up hvac control module the only thing I can find is the dual climate control and nothing behind the dash. You would think googling it would bring up something behind the dash but I can't find anything. I've researched this for weeks...