Hey i have an 08' Hummer H3 this is the second time driving to work in the morning that the temp guage will completely turn off and a A/C OFF light flashes on an off. Ill be driving for a few more minutes an the guage will randomly just turn back on. the guage turns back on to normal running temp. the car is not actually overheating. Today it happened twice while on the drive to work. Im thinking its a sensor problem didnt know if any of you guys have had this problem an knew which sensor it was. Any help would be greatly appreciated, thanks guys...

P.S.- the dealer says theyll only waive diagnostic fees if it falls under warrenty so i want to diagnose it myself before i start going broke.

 

You need to replace the ECT sensor

 

Will this cause da transmission to slip, I hve da same problem wit my 08 hummer h3 the temp gauge will go dwn not working at all then the ac light flashes in the instrument panel.but my hummer is also slipping in da transmission.is that all connected.plz help I'm thinking I hve to buy another transmission.thanks

 

yes hi ...all this are with me now same model 08 h3 ... so please any i deia what to do ? or what sensor are need to be check .. thank you all

 

Has anyone came up with a good solution on this issue because I am having the same issue right now and don't know where to start to get it fixed

 

This is why we should AVOID digging up 3.5 year old posts, and instead start a NEW one with your specific question.

What same issue? The AC Off DIC Message showing and then disappearing and temp gauge shutting off, transmission slipping???

If your DIC shows AC OFF and it stays that way, and your temp gauge is working all the time, then you have a different problem.

So which is it?

 

I was talking about the a/c off light is it the temp gage, sensor or thermostat?

 

Mine is doing the same thing. I have replaced the ECT sensor with no change. If you pop the battery cable off for a minute it will clear it might be good for 8 hours might be good for 3 days before the message reappears.

 

Disconnecting the battery does not clear anything, the PCM stores the last 300 ignition cycles, power or no power.

The temp gauge just reads input from the sensor, so even if the gauge were bad, it would not cause the AC to turn off, it just wouldn't show a reading. If the temp gauge shows no temp it points to the temp sensor. The sensor itself is monitored by the PCM, when it does not know what temp the coolant is, it defaults to the assumption of overheating to err on the side of caution. The first layer of overheat protection is when the PCM turns off the AC.

 

I apologize for using the incorrect terms. When the AC OFF messages appears, I can remove the battery cable and it goes away for a time. The error might reappear in 8 hours or it might take it 4 days to reappear. I'm trying to find a solution without replacing parts unnecessarily. Like I said I have already had the ECT sensor replaced and it did not resolve the problem. Does someone believe the problem is with the PCM? The thermostat?