H3 UIC Code A/C Off

[Cyouincourt007]

I found a thread here about this but no content, may of been lost in the hack. If this is a redundant thread my apologies in advance.
The issue.... Every so often i get an A/C OFF alert in the UIC. This morning i got the alert/code upon startup to head to work. Proceeded to work and on the hour long drive noticed the temperature guage stayed on C and did not move. Also tried to use the A/C and it did not turn on. Any thoughts? thank you



*was able to see the related thread now but nothing conclusive that i took away from it.

 

[mrchew]

I found a thread here about this but no content, may of been lost in the hack. If this is a redundant thread my apologies in advance.
The issue.... Every so often i get an A/C OFF alert in the UIC. This morning i got the alert/code upon startup to head to work. Proceeded to work and on the hour long drive noticed the temperature guage stayed on C and did not move. Also tried to use the A/C and it did not turn on. Any thoughts? thank you

I had that on my 08 Hummer. I replaced thermostat and it finally went away.

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[Cyouincourt007]

Thank you for the prompt response. Mine is an 08 as well. I've read on here that the new thermostats cause the engine to run hotter. Mine rarely makes it to the halfway mark. With the new one I heard it will ride at halfway and pass the halfway mark. If thats true any way to avoid that? It seems were on our way to a brutally hot summer in south florida and riding hot is not preffered. Any options like removing it and not even installing one.

 

[Enter Hummer]

Do you mean not re-install the thermostat? The only real problem with that is your engine will run too cold. Correct me if Im wrong but I heard that the truck companies designed the pistons in the engine to form an oval when cool, and as they warm up they return to circles for some reason I cant remember. We run our suburban like that with no thermostat for over-heating reasons. It runs perfectly, just very cold.

 

[Cyouincourt007]

Yea, Id rather run no thermostat and cool than with one and run hot. It is a nasty hot summer here but not sure if that makes any difference.

 

[mrchew]

Thank you for the prompt response. Mine is an 08 as well. I've read on here that the new thermostats cause the engine to run hotter. Mine rarely makes it to the halfway mark. With the new one I heard it will ride at halfway and pass the halfway mark. If thats true any way to avoid that? It seems were on our way to a brutally hot summer in south florida and riding hot is not preffered. Any options like removing it and not even installing one.

Mine shows higher than half way but I think it has more to do with temperature range of thermostat. They sell with all types of ranges I've seen. It's not that you're running hotter it's more that the range is lower on new that it'll read higher on gauge. Mine has been running fine for 6 months. If you don't change it you'll risk the thermostat not opening and not cooling engine and that would be way worst than gauge showing higher temp.

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[deserth3]

You're better off with a properly functioning thermostat. The Gage is just an indicator. And not that accurate.
My 06 runs normally at just over 1/2 to 3/4. And I run in the Utah desert.
GM did come out with a software fix for those that see the half way Mark as too high. It just shows lower on the gage. This fix only works on 07 and above. Does not work on 06.
If you are worried about the annual temp get a scanner Gage or something similar that will get the true temp from the computer.
Running with out a thermostat will eventually ruin your catalytic converter. Because it will always be running rich.

If your truck does overheat. You'll get a message on the dash and the truck will turn off the ac

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[Cyouincourt007]

Understood,makes sense, thanks for the info, will get new thermostat and install asap. :cheers:

 

[Happy Hummer]

I'm pretty sure a 180 degree tstat is available.

 

[alrock]

Nice answer Desert, thanks. Yeah, less harmful with a fully open stat than a closed one, but not completely unharmful.

And it sucks in winter (in cold climates) when it's stuck open. Takes forever to get the vehicle warm inside.