My thermometer needs to be calibrated... It's off between 4 and 6 degrees.... Is there a trick to calibrating it?

 

I believe the only way to fix this, is a new sensor/sending unit.

They are easy to replace, they just plug in (after you remove the trim piece covering them).
Not sure if you can order one from AutoHaus or not. Not sure WHERE to get one.

 

My question to you is are you sure it is out of calibration? That outside sensor has a multitude of phases it goes through and it's pretty hard to figure what phase it is in at any given time. It displays according to a schedule that is complex. If I were you, I would spend some time reviewing the associated systems that rely on that sensor and try to figure out when it is actually reading/indicating the outside temperature. I do know it is a thermistor, and its a resistance rating relative to the outside temperature, but to figure out when it is reading/displaying the outside temp (not to mention you pretty much have to be facing the wind/breeze or you'll be a false reading from engine compartment) and also, you may be too close to a heat source which also could be giving a false reading. Why do you need it to read outside temperature so accurately?

 

I've found that it will read quite high if sunlight is hitting it too...just sayin'.

 

GG is right, that sensor does not always display actual temperature, unless you have been driving for several miles.

Also, they can be accurate at speed, provided the sun is not beating down on the pavement and throwing it off.

 

Mine Started to read 135f last week and been there since

 

ANOTHER confirmation of global warming!

 

I think that, if they come unplugged, they read high, you might yank the facia off and see if it is still plugged in.