Mirror defrost changes temp sensor reading

[docfoley]

I destroyed my standard power fold mirror against a tree ( backing while looking over my right shoulder :-0 so I replaced it with a non folding aftermarket tow mirror. Everything is fine until the defrost is activated. When activated the ambient temp reading drops to -40 and it throws a temp sensor check engine light. Remote start fails in the winter when defrost is auto activated. Under normal conditions the temperature is reading correctly. The mirror was plug and play so I did not have to do anything to the wiring. My sense is that this is a ground issue but I don't have a diagram to check. Anyone with an insight?

TIA

 

[Daw14]

If you still have the original mirror , swap the OEM sensor onto the aftermarket mirror . Or get a new OEM sensor , looked a few days ago as someone had a similar issue.
About $12.00 at most dealers.
Always replace sensors with OEM, the brand it came with from the factory . This holds true for any brand or make vehicle. As they each have their own specifications,that aftermarket does not always meet.

 

[docfoley]

It was w destroyed and I don't have it. The odd thing is that the sensor that came with the mirror works correctly... until the defrost is turned on. I can purchase a new one and see if that solves the problem