Impala Forums banner

Ambient Temp Won't Reset

37K views 30 replies 11 participants last post by  GrizChev 
#1 ·
I disconnected the negative bat terminal to replace the heater & a/c controls, cruise control switch, and radio control switch. I reconnected the negative bat terminal when I was done.

I now have ---F displayed in place of the outside temperature. I tried to reset by pressing the a/c and recirculation buttons simultaneously like I read in other posts. No change. Taking a chance, I replaced the sensor and again, pressed the a/c and recirculation buttons simultaneously. Again, no change.

Any suggestions on what else I could check?

Thanks!

Mark
2007 Chevy Impala LT, 3.9L V6
 
#2 ·
If that force-reset doesn't work (make sure you pressing the recirculation button and not some other button), then it sure sounds like *something* was left disconnected somewhere that is causing the ambient temp sensor to no longer work...

I have done the ambient temp force-reset before and it definitely works. But usually, that just forces the temperature to update to the current ambient temp (from one temp to another) - not from "--F" to the current temp... The fact that you are getting the "--F" tells me that the DIC is not receiving any signal at all from the temp sensor...

Sent from my HP SlateBook 10 x2 PC using Tapatalk
 
#4 ·
Thanks for the replies.

Switches were reconnected correctly. There's a small plug that's unplugged from the old switch and plugged into the new switch. Pretty basic and the devices they control work correctly.

I tried driving around for a while then did the a/c - recirculation button reset again. No change. Temp still displays ---F.

Electrical issues are a pain to troubleshoot. I guess a trip to the dealer is in my future.

Mark
 
#6 ·
One additional suggestion:

I have replaced the ambient air sensor on several GM cars - simply unplug the old sensor and plug in the new sensor. A friend at a Chevrolet dealership part's department told me that it is common for the female receptical plug to become corroded due to the water instrusion at the front of the car and to check the plug for corrosion, and install some dielectric grease into the cavity. He said GM makes a female ambient air temperature sensor receptical pigtail so that the whole harness does not have to be replaced (there are several different pigtails depending on the vehicle).

You may want to remove the new sensor and look inside the receptical connector to see if it is clean and has no corrosion. If somewhat corroded - you may be able to clean the inside with spray electrical cleaner and a small toothbrush or Q-Tips. If severely corroded, you can replace the terminal with a new pigtail connector from GM.

It is POSSIBLE you received a bad sensor. Did you buy a GM one (they are inexpensive)?
 
#5 ·
Did you have to disconnect the ambient temp sensor when you replaced the original parts (before you tried replacing the temp sensor)? If so, any chance the pins got bent when reconnecting the ambient temp sensor or something like that? Have you looked at the ambient temp sensor connectors (while unplugged) to make sure the pins are OK? It sure seems like there is a connection issue with the temp sensor.

Very strange... I'm out of ideas!

Sent from my HP SlateBook 10 x2 PC using Tapatalk
 
#8 ·
BUMP
my dad's 08 Impala LT is having the same problem. Him and his mechanic friend did some work and when they were done, the ambient temp reads --- F. I replaced the ambient temp sensor that goes right behind the grille and the reset with no change. Anybody have any other tips?
 
#9 · (Edited)
This may be useful: When I replaced my AC & Heater Control Switch, the ambient air temp went from reading accurately to --- F. For the life of me I couldn't figure it out. Turns out for some strange reason the software in the car couldn't mesh the new control switch with the ambient air temp sensor, causing it not read at all. A trip to the dealer, one hour and $30 later, they did a software update (I don't know which software was updated but it required a Tech-2 and a computer) and it started reading fine again.

Hopefully yours won't come to that, but I just wanted to share my experience.

Edit: I just wanted to add that my car is an 08 LTZ.
 
#11 ·
If you're talking about my post, yes. The temperature / AC controls.
 
#14 ·
I am experiencing the same problem on a 2011 Impala LT. I replaced the HVAC control panel due to a failed toggle. The ambient temp readout then went to ---F. Reset doesn't work. The above thread speaks of dealer software updates. Any solution without dealer involvement???
 
#16 ·
You could try a hard reset disconnect the battery for 2 minutes then touch the negative and positive battery cables together for 30 seconds. When you start it though let it idle for about 10 minutes and then drive it gently for a few miles while the tcm learns a nice smooth shift pattern. Sometimes hard resets fix all kinds of things worth a try cannot hurt.
 
#21 · (Edited)
There are some claims online that shorting pos to neg resets this or that. But what it does is fry the circuits and the battery and possibly explodes the battery.

Some online counter saying disconnect the battery from the car first. But if it's disconnected then how does shorting POS TO NEG POSTS reset anything? What happens is you get hurt and the battery boils-off and sometimes catches fire.

There are various oem reset procedures that also have other connection requirements varying by manufacturer. It's not what is portrayed here.
 
Top