Has anyone had an issue with you outside temperature readings being wrong? i just bought a car and was told after it was tuned the ext. temp was always 69 degrees. and if you wanted a/c you had to set the temp. to below 69 and above 69 for heat. that worked fine, but today the ext. temp slowly dropped until it reached -38 degrees. so now there is no way turn the A/C on. could this be fixed with another tune? or is the senor maybe bad or blocked? how would i check that? has anyone else seen this?

 

It's your outside air temperature sensor. You can get one from your dealer or Gene Culley pretty cheap.

 

Posted by trussme

Could be A faulty outside air temp sensor
The sensor is located on the right (passenger) side of the car, on the outside of the frame rail in the very front by the headlight.

It is held onto the mounting hole on the frame by a plastic push-in clip.

Just pull the clip out of the hole on the frame, release the plug for the wire (the plug has a release clip, pry up on the clip and the plug will release).

Then just put in the new one and you will be in business - it takes a few minutes of driving for the sensor to start reading the outside temp - you have to be moving.

GM Part # 10248414 is aprox. $10 from the dealer and just plugs in.


The sensors are either resistance temperature detectors (RTD's) or Thermistors. The resistance of the sensor changes with the temperature.
If you have any corrosion in any of the associated connectors it will increase the resistance that the climate controls is reading.
The resistance across the two sensor wires could be almost infinity,
in that case your display would read a low temp.

Once the old sensor is removed, the HVAC defaults to 69* and will let the AC cool.

 

awesome. thanks guys! do i get to this sensor from the top or the bottom? anyone happen to have a pic??

thanks again. i love this place!

 

Mine will read a little bit low on first start up in the morning but other than that it's right on.

 

3 cars 3 different temperature readings there all wrong!

 

You can see the tip of the sensor from the bottom radiator shroud, but to remove it you will either need to raise the headlight, and pull the black plastic bezel off and then reach down and grab it, or by reaching down along the frame by the radiator shroud but that's a long reach. Also check the wiring harness first to see if it was ever unplugged by the previous owner. Once you spot the sensor you can just follow the connector back to the main harness. Most likely you just need a new sensor. Mine went out after about 6 years, and the temp reading in the car did exactly as yours. Nothing concerning this sensor would ever be affected by a tune, nor would a tune fix it.

 

Shortcutted, Thanks

 

i tried looking and i found a cable that's not even plugged in. but i can't find the sensor. tomorrow i'm going to try to stop by my mechanics place and see if he can look at it for me. i wish i could have found it. would have been nice to get that fixed now.

 

Be certain that the unplugged cable isn't for your underhood lamp, which is also in that general vicinity. If your hood lamp is working then obviously thats not it. Is the unplugged cable near the frame below the passenger side headlight, if so thats it. Should have two wires.

See yellow circle, thats the temp sensor tip.

 

Great pic and outstanding info. Good job!

 

looks like i don't have one. the previous owner had a Vararam installed and the plastic you have circled isn't there on my car. i guess i'll have to order one and find a place to install it.

 

Weird. I kept mine when I did my Vararam install. I wonder why he got rid of it.

 

Great write up and pics

 

i don't know. it was done professionally, but i don't think it was done the best. i have to get the car up on a lift and look at it from the bottom. i don't think there is anything wrong, but it just isn't the way i would have done it.

 

The good news is you have identified why the reading is wrong , the part is one of the least expensive on the C5 and the replacement is quite straighforward.

 

Be sure you install it as the factory did. You need to make sure the sensor tip is in the incoming air stream for proper readings. I believe all you need is a plastic pushpin to hold the sensor in its original location. You can get the pushpin at any parts store. Good luck and let us know if this fixes the problem.

 

I just picked up a sensor at my local dealership (most expensive place i looked , but when you factor in shipping costs, it was about the same and i didn't have to wait). i hooked it up and everything works perfect! now i just have to figure out how to mount it permanently. i'm thinking maybe a zip-tie. kind of ghetto, but it should work and you wouldn't notice it. and i have those laying around. i don't have an extra screw and bolt that size.

 

A tip tie will work. But I'd recommend you get a bolt and make the zip-tie a temporary fix.

 

that's my plan. make sure i like where it is. and then next time i'm at lowes, i'll pick up a bolt.