Heat gauge and AC not working all of a sudden
 

Driving home today and the AC just stopped blowing cold, and the heat gauge dropped and reads nothing. The DIC temp reading is just dashes. Car runs fine otherwise. The HVAC blower works, so does the panel selector. The AC light lights up on the panel, the clutch doesn't seem to be activating thou, and of course, no cold air. It's supposed to be in the high 90's this weekend ....really want to fix this LOL

Checked the diode AC clutch fuse under the hood, its a funny looking black fuse located in the #9 position (at least I think its a fuse), and my OHM reader reads nothing on it, so I'm thinking this is the issue

Anyone else have any feedback. Its a holiday here today (Canada Day), so I can't just run out to NAPA and see if they have this funny looking fuse. Its black, about the size of a fuse, has a little arrow marking on top, and the two legs are not side by side, but rather perpendicular....what the heck is this thing?

It is a relay, sometimes they can reset themselves when you remove them, sometimes they do not. I had this happen with my old Colorado, I just learned to to keep a spare in the console, also for the coorado, i had to go to dealer and get it, the ones at the local parts store were not the same.

is this what the pic looks like
http://www.mcmelectronics.com/conten...s/s4/DIODE.jpg

Do you have a CEL displayed? When my DIC temp display was the dashes the CEL code was P0128. Engine Coolant Temperature (ECT) Below Regulating Temperature. Replaced the T-stat and all was good again.

Can't tell you if it affected the A/c as it was Feburary in Michigan but I would think that if there were issues with the cooling system it (BCM) would prevent the A/C from working to avoid possible overheating/damage to the system.

That's the one....

never mind, its not the diode ...switched it with the wiper diode and still doesn't work. Not the relay either, as I switched that with the rear hatch release relay.... no change

Anyone have any ideas?

like he said replace the stat

There is no CEL .... will take it in on Monday get scanned.

A bad coolant temperature sensor could cause the gauge to be inop and since there would be no temperature reading to the BCM, it would command the A/C to not come on.

Check this thread for the procedure to replace the thermostat that a couple have already mentioned as being a likely cause - https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/ - it may or may not throw the p0128 code via the engine check light.

Or as chevyMgr says, it also could be the temp sensor.