986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Does the ambinet air temp sensor figure into when the cooling fans run?

austinporsche · 05-21-2023, 07:46 AM

I

I recently "lost the ambient air temp sensor and connector to a small mammal.

I have a friend who had a donor car from which I got a new pigtail and used some round "bullet" connectors to connect the sensor back into the harness.

I tested continuity on the wiring and all seemed good.

I assumed that the sensor didn't have polarity, i.e., it was just a passive resistive element, as the two wires on both the harness and pigtail ends appeared to be the same (there were no color markings on either sensor wire to indicate otherwise).

Anyhow I was driving today with the top down and with a little sunlight at my back I was finally able to see the middle LED information display, and the temp was displaying "- - - F", i.e., no temp reading from the sensor.

Any idea what is up? I am confident in the continuity of my connectors. Is there a polarity to the sensor?

And I also noticed that even when the coolant temp reaches 195F (I have a VeePeak WiFi ODBII reader that renders engine data on an app on my phone),I don't hear the fans running with the AC off and the coolant temp over 190F, but the fans do run when the AC is on (even when coolant is "cool", i.e., 90F).

Could the fan relay circuit needs the ambient air temp as input to determine when to run the fans or not?

Any help/direction would be most appreciated.

05-21-2023, 07:46 AM	#1
austinporsche Registered User Join Date: Aug 2019 Location: Austin, TX Posts: 42	Does the ambinet air temp sensor figure into when the cooling fans run? I I recently "lost the ambient air temp sensor and connector to a small mammal. I have a friend who had a donor car from which I got a new pigtail and used some round "bullet" connectors to connect the sensor back into the harness. I tested continuity on the wiring and all seemed good. I assumed that the sensor didn't have polarity, i.e., it was just a passive resistive element, as the two wires on both the harness and pigtail ends appeared to be the same (there were no color markings on either sensor wire to indicate otherwise). Anyhow I was driving today with the top down and with a little sunlight at my back I was finally able to see the middle LED information display, and the temp was displaying "- - - F", i.e., no temp reading from the sensor. Any idea what is up? I am confident in the continuity of my connectors. Is there a polarity to the sensor? And I also noticed that even when the coolant temp reaches 195F (I have a VeePeak WiFi ODBII reader that renders engine data on an app on my phone),I don't hear the fans running with the AC off and the coolant temp over 190F, but the fans do run when the AC is on (even when coolant is "cool", i.e., 90F). Could the fan relay circuit needs the ambient air temp as input to determine when to run the fans or not? Any help/direction would be most appreciated.