So... What is it that I need to replace when I get "Ice Possible" displaying on the console even in the middle of summer? Gotta be just a sensor of some sort. Thermometer on the rear view mirror is correct, reading in the 90's as it should on summer days like this. I know I'm in Maine, but ice isn't ALWAYS possible, lol. Can't be in the BCM, as I had that replaced last year and was getting the message even before that. I can simply clear it by hitting the button, but it's a minor annoyance. Sometimes it comes on when I first start it, sometimes not until 20-30 minutes into my drive. Seems random. Thanks!

 

Mine does the same thing when it rains. I read it had something to do with the temp sensors in the front grill area but I haven 't messed with it.

Tim

 

Thanks for the info Tim. Interesting. Doesn't necessarily do it specifically in the rain here, however on the east coast we do have more humidity than most areas. I do see fairly cheap ones for sale listed as "ambient temperature sensor", however after looking at 15-20 of them, everyone seems to list a different part number, so not sure which one would be the right one for my 2003. Guessing I'd have to have the dealer look it up by vin number to get the proper match. I also see there are several listings for the "ambient temperature sensor connector", so might be another step close to finding the culprit. Not even sure if this is something that's easily accessible that I could replace myself or not, as I'm certainly no mechanic, (I know my way around enough to change spark plugs, change oil, trace some wiring, etc...) but certainly gives me a place to start looking. Odd that the external temperature shows correct on the rear view mirror display though if either of these were failing, but probably just failing enough to pop the warning when it randomly refreshes without effecting the data i suppose. Thanks again.

 

Follow up... does number 10 or 11 in the diagram look like right I'm on the right track to fixing the issue?

 

fi you say mirror is correct then it probably is not 11 if AC works fine probably not 10. you have 1, 6, 7 left i guess. you probably need a good scanner to interface with the sensors to see which one is giving the wrong temp.
there are also 2 more bolted to the passenger side front bumper.
it would be around the headlight location cant miss it. they look like grey harness caps.

 

Cool, thanks. Yeah, mirror temp seems right, and AC works fine. I'll take a peak in the morning at all those locations and hope it's just a loose connector or something obvious. I hate to take it to the stealership and pay $95 an hour for diagnostics on a 5 minute scan, assuming the scan would even show it, since it seems to pop on randomly, sometimes when I first start it, while other times I can drive for an hour or more before it comes on,

 

I had the same problem a few years ago on a 2004 Trailblazer, the AC quit working also in the middle of summer, changed the sensor (HVAC) no other problems.
Got the sensor from Amazon, $17 if I remember...

 

I was under the impression that it was the 2 in the front bumper behind the grill. Again, I haven't got into yet.

Tim

 

As I recall there are two -ve co-efficient thermistors located near the RH headlight.

You could try swapping them over to see if the fault goes with the sensor or measure their restsiances. If you do remove a sensor with the battery connected, it could take several hours for the system to re-average (took mine a whole day)

 

Thanks. Perfect. Found them super easily in the front RH bumper area right underneath the headlight, swapped the plugs between the two sensors and the "ice possible" went away with the HVAC one, and mirror temp read "OC" (connection issue) on the other. Told me exactly what the issue was. Ordered 2 new sensors on fleabay (might as well do both while I'm at it), since they were only $6.99 each with free shipping. Cheapest H2 fix I've ever found, lol. Never would have figured it out without this forum. You guys rock. ACDelco OEM GM Part #25775833 if anyone else needs them.