Erratic Ambient Temperature Reading (2003 Ram 3500)

[VMF-113]

Am experiencing very erratic outside ambient air temperature fluctuations on my overhead display. Display will sometimes read as high as 130 degrees, and remain so for several hours or dats. I have replaced several sensors, plug assemblies and related wiring going to the sensors. This has been occurring various times in the 20 years I have owned my truck.
The only thing I haven’t replaced yet is my actual overhead console assembly. That’s next on my list.
Any thoughts you might have? Any similarities you may have heard over the years?
I depend on knowing my outside temps, especially for road surface temperatures here in Montana in our winters.
Your thoughts and suggestions are very much appreciated.

Mark Everton
Columbia Falls, MT.

 

[Timd32]

Can't make a PDF for some reason.

Either way here are some pics.

Found this:
If the CMTC/EVIC display indicates 54° C (130° F) or the ATS sense circuit is shorted to ground, the temp display will be 54° C (130° F) to indicate a SHORT circuit condition.

 

[Crunch]

Am experiencing very erratic outside ambient air temperature fluctuations on my overhead display. Display will sometimes read as high as 130 degrees, and remain so for several hours or dats.

Welcome to my world. That's been the story of my truck since the day I bought it new and drove it off the lot. 130* is the most common incorrect reading, but in the winter it will read -40*, and other times it will jump around. The best times for it to have the correct reading is when the outside temperature is in the 40s or 50s. I took it back for warranty repair several times. They replaced the sensor, but it didn't fix the problem. They never replaced the overhead console, and I eventually got tired of taking it in and just gave up. 20 years later and it's still doing it, but I am beyond caring.

 

[Timd32]

Welcome to my world. That's been the story of my truck since the day I bought it new and drove it off the lot. 130* is the most common incorrect reading, but in the winter it will read -40*, and other times it will jump around. The best times for it to have the correct reading is when the outside temperature is in the 40s or 50s. I took it back for warranty repair several times. They replaced the sensor, but it didn't fix the problem. They never replaced the overhead console, and I eventually got tired of taking it in and just gave up. 20 years later and it's still doing it, but I am beyond caring.

From the above -40 says the circuit is OPEN, 130 is saying the circuit is shorted.

Being the harness looks to be hooked to the hood, I would look at that harness and pinch points and bending areas.

 

[VMF-113]

Timd32,
I appreciate your help and time in replying VERY much. It will surely give me a great starting point. It’s certainly is way more involved than I would have thought. Again, thanks!!

Crunch,
Thanks, too, for letting me know that I’m not alone in my misery! I may end up like you if I can’t resolve it! I’ve had my truck since new, and have almost 600,000 miles on her! She’s like family! Thanks for your support,

Mark