No outside temp display on my 97 C280. I replaced the outside temp sensor with a used one from EBay, but still no display. I wonder if its an instrument cluster issue, or perhaps a break in the circuit somewhere. Are there any tests for the sensor? No outside temp display on my 97 C280, as well. I replaced the outside temp sensor with a used one from EBay, but still no display. I wonder if its an instrument cluster issue, or perhaps a break in the circuit somewhere. Are there any tests for the sensor?

 

there is a bulb in the cluster behind the outside temp and odometer and clock. it can be replaced.if its not the bulb then its the pixels that went bad.

 

The old sensor had been cut off after a minor front end collision. After I reatttached another sensor, just get a blank display...the bulb behind is OK, I guess I will have to get it reprogrammed with the bloody Merc Star !!! Is there any test for the sensor itself (EG: Resistance value) to make sure its OK?

 

1997 Mercedes Benz C 280 (202.028) L6-2.8L (104.941)
Outside Temperature Display Sensor: Description and Operation
Outside Temperature Sensor
The outside air temperature sensor (B14) serves for measuring the outside temperature.
The resistance of the outside air temperature sensor depends on the ambient temperature and the speed. When the outdoor temperature increases
the resistance decreases. This information is relayed via the instrument cluster and serial interface (K1) to the pushbutton control module.
This information causes a slight reduction or increase of the temperature set on the pushbutton control module. This provides greater comfort by
adapting the temperature to the temperature perceived subjectively by the passengers.
The interrelationship between the outdoor temperature and vehicle speed prevents an excessively high temperature from being relayed to the
pushbutton control module when the vehicle is standing still or driving slowly resulting from heat being radiated from the engine.
The temperature measured last is used when the ignition is switched off and on and at speeds below 20 km/h .

According to this you can take it out, connect to instrument, have a heatgun or hair dryer and see if resistance is changing.