Ambient temp sensor issue p0072

[B8Nate]

So I just finished up rebuilding my head from burning a valve. I have 2 issues that I'm sure will be simple fixes. Car is operating and running fine. No leaks (knock on wood) and running just fine at normal temps, no weird noises, etc

But my speedo is not working, I haven't pulled the code for that.
My question in this post is about my p0072 code. My A/c is not working I know because the ambient sensor is faulty or wiring is faulty. P0072 states "low circuit" for ambient sensor. So does that mean the sensor is bad? It was perfectly fine before the rebuild, which makes me think the wiring somehow could of gotten damaged? So my question is if I check the wiring with a multimeter on the ambient sensor with car running will I be looking for 12-14v or what? If I'm getting that amount of power, that would tell me the sensor is bad. Thanks in advance for letting me know what type of power should be shown for the ambient sensor wiring.

[B8Nate]

Ok so I installed new ambient sensor today. Still nada. I've taken the front bumper off. Traced the wiring all the way back to the firewall, from front bumper location, to under driver side fender, too firewall, no breaks or kinks, all wiring is wrapped in that heavy duty ribbed wire wrap and it's all intact. Tried both old and new sensor. I've tried blowing the connections out with air to make sure there's no dirt or debris. Idk what else to do. Still NO A/C and NO temp shown on dash, wiring looks okay and sensor is new, also tried with old sensor as well. Is there a fuse that could be blown? I've checked all fuses in trunk location and driver side door location and none listed as "ambient sensor" so I'm sure it shares a fuse with something else but idk. Ugh this is the last of a list of problems I'm trying to solve and I hate to take it to the stealership for a minor problem such as this and get charged an arm and leg.


By the way: I checked the resistance on both old and new sensor. Both read the same. So obviously sensors are okay. Wiring had power. I'm not sure exactly how much it should have. I checked resistance and voltage. It got power both ways. I just don't know how many volts is suppose to be running thru the wiring. I'm at a lost now. Wiring has power. Sensor has power. Why isn't it working?





Sent from my iPhone using Audizine mobile app

[S4'ed]

The temperature sensor changes resistance with temperature. When connected, one pin measured to ground, DC volts, will have somewhere between about 2V to 10V (might be between 1 and 4V...not sure, these sensors are typically powered with a +5V full-scale signal). If you pour some ice water on it, the voltage should change.

What does the dash outside temperature display show? Blank? or a very low (cold) temperature? Very cold means the circuit is open between the sensor and the module that it connects to (Instrument Cluster?). If it shows a hot temperature (or a blank), the sensor wiring is shorted to ground somewhere.

"Low Circuit" diagnostic typically indicates a short to ground.

[TurboNate]

Does your cooling fan turn on right when you start up the car?


Sent from my iPhone using Audizine mobile app

[B8Nate]

Does your cooling fan turn on right when you start up the car?


Sent from my iPhone using Audizine mobile app

Yep fans come on pretty much 5-10 seconds after I push the start button. I unplugged the ambient sensor and the A/C is working and CEL went away. Then I plugged back in and it's showing the correct temp but A/C isn't cold. So I just left it unplugged. Idk lol


Sent from my iPhone using Audizine mobile app