Troger Posted May 23, 2022 Report Share Posted May 23, 2022 Hi all! I've been searching for hours online and looking all over my salvage 2018 Ford Edge (2.0 EcoBoost), and I can't for the life of me find the AAT sensor. When I start the car it shows -40 for outside temp, but after driving for about 5 minutes is starts showing the correct temperature. Not a huge deal, but it's starting to get hot out and the AC won't work until the outside temp starts registering correctly. So, I pull the front bumper off and I'm following every connector I can find and I don't see the sensor anywhere. It's got to be there or else it would never register, but I have the haynes manual, and the Internet and I can't find it anywhere. I know what the sensor looks like... and it should be somewhere between the grille and the radiator I would think, but I'm stumped... it's a $6 fix that I've spent hours trying to run down If anyone could send me a picture of it's location I'd be forever grateful! https://parts.ford.com/shop/en/us/electrical/sensorsdevices/sensor-assy-7821147-1#/partMatched Quote Link to comment Share on other sites More sharing options...
Haz Posted May 23, 2022 Report Share Posted May 23, 2022 (edited) Below are PDF download links to relevant sections from the 2018 Edge Workshop Manual... Ambient Air Temperature Sensor Removal and Installation - 2018 Edge Workshop Manual.pdf Front Bumper Cover Removal and Installation - 2018 Edge Workshop Manual.pdf System operation description... Outside Air Temperature The Ambient Air Temperature (AAT) sensor is hardwired to the PCM through separate input and return circuits. The PCM provides a reference voltage to the Ambient Air Temperature (AAT) sensor and monitors the change in voltage resulting from changes in resistance as determined by outside air temperature. The PCM sends the ambient air temperature data to the GWM through the HS-CAN1 . The GWM sends the ambient air temperature message to the HVAC (part of the FCIM ) over the MS-CAN . The FCIM filters the data and sends the ambient air temperature filtered data back to the GWM over the MS-CAN . The GWM sends the ambient air temperature filtered message to the IPC over the HS-CAN3 . The FCIM is programmed to update the messaged outside temperature data at different rates depending on several criteria to prevent false temperature displays due to a condition known as heat soaking. Heat soaking is where the outside air temperature is hotter in the location of the Ambient Air Temperature (AAT) sensor than the actual outside air temperature. The outside air temperature display update strategy requires a starting temperature to update from. This starting temperature is controlled based on the length of time the engine is off and the engine temperature. When the engine has been off for longer than 6 hours, the update strategy begins with the unfiltered ambient air temperature input to the PCM . If the engine has been off for less than 6 hours, and the engine coolant temperature is less than 49° C (120° F), the update strategy begins with the filtered ambient air temperature equal to the unfiltered ambient air temperature. If the engine has been off for less than 6 hours, and the engine coolant temperature is greater than 49° C (120° F), the update strategy begins at the stored previous outside air temperature value. When the sensed outside temperature rises and the vehicle speed is above 33 km/h (21 mph), the outside air temperature display updates after approximately 90 seconds. As the vehicle speed increases, the outside air temperature display updates at a faster rate that is proportional to the increase in vehicle speed. Once the vehicle speeds exceeds 81 km/h (50 mph), the display updates without any delay. If the vehicle speed drops below 33 km/h (21 mph), the update delays reset. When the sensed outside temperature drops, the display updates more quickly following the drop experienced by the Ambient Air Temperature (AAT) sensor. Good luck! Edited May 23, 2022 by Haz 2 Quote Link to comment Share on other sites More sharing options...
Troger Posted May 23, 2022 Author Report Share Posted May 23, 2022 Thanks Haz!! Those manual images are fantastic... I can't find that info in the haynes manual at all So that entire cable is just missing from that location on my vehicle... The front shutter that the AAT mounts on was trashed and I replaced the entire thing, but never saw that cable anywhere. I'm going to have to see if I can get a copy of whatever manual you are pulling those pdfs from as that is super detailed. The cable must be somewhere though as it does eventually register an external temp. Thanks, Troy Quote Link to comment Share on other sites More sharing options...
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