Outside Air Temperature Gauge (OAT)

[BrianH]

The OAT gauge in my 1993 300CE has consistently read 20˚ below the actual temperature. I have replaced the sensor without effect. I've gotten used to doing the math (60˚ indicated + 20˚ = 80˚ actual) but wonder if there is an adjustment that can be made?

 

[gsxr]

No adjustment is possible. You can test the sensor and the display using the factory documentation (click here). Although rare, sometimes the display itself gets out of calibration and must be replaced. Good used ones are available on eBay.

 

[BrianH]

Thank you.

 

[Surf Blau]

When I bought my car, the PO told me that his MB-knowledgeable friends had "diagnosed" the wonky OAT to a faulty sensor and thus he gave me a new (original) sensor with the car. However, the way the display acts in my car (see attached video) made me suspect a faulty display rather than the sensor - which was confirmed after testing the new sensor a few days ago where there was no change in behavior.

What's even weirder than the way it acts is that it sometimes doesn't start showing "values" until I switch on the headlights, which makes me suspect a grounding error in the display itself. I don't have much experience from the W124 series before getting this car, but I've never had similar issues in all my years working with W201s. During all these years I've never had a faulty sensor either, though..