outside temperature sensor

[rustyrescue]

that fact I am thinking why the outside temperature display reads 0 degrees indicates just how good my project Cav is. I have located the sender under the front, can I test the display by shorting the wires out? if I can make it read anything but 0 degrees it will confirm the sensor is at fault.

[Robsey]

The sensors tend to read high when faulty.
Usually telling you that it is in excess of 30°C.

I would not do a direct short of the pins.
The correct resistance range is between 100 ohms and 1.5k ohms.
Outside of this is considered a short circuit or a disconnected sensor.

Typical sensors can be obtained quite cheaply.
And are fitted to virtually all Vauxhalls models between 1988 and 2008 (dependent upon trim level).
So plenty about in scrap yards, ebay or your Vauxhall parts supplier.

[vexorg]

Quite often it'll be the connections corroded as it sits close to the road.

[Robsey]

Yes - it would hint at a higher than expected resistance through the temperature sensor circuit.

I have never had pin corrosion issues, but as David suggests, the sensor is low down near the road, close to road spray, puddles and the like.
So it is worth checking the connectors both under the bumper, and also
up on the bulk head close to the octane plug / drain scuttle "elephant's trunk" drain hose.
Look for the blue and the blue/white wires.

[rustyrescue]

perfect thanks, so the sensor itself should read typically in 100 to 1.5K ohms range, I can check that. Its a silly thing but nice if I can correct it.

[Robsey]

I have looked on my tables, and it appears that the resistance across the sensor should be approx 200 ohms at 0°C.

Using a variable resister should allow you to check the accuracey of the sensor.
But remember any indication of temperature change on the dual info display or board computer is not instantanious.
It is quite slow 0.5°C at a time, not just a time lag.

[cavalier1990]

My temp sensor reads lower than it is, so will say 5 oC for a day typically 10-15 degrees. I changed it quite a few years ago, as there was something wrong with it, it might have been reading too high, but when I changed it it I noticed it was reading a lot lower. Never looked into it further, but seems the opposite problem most others have had. Maybe wiring?

[vexorg]

Could be a fault in the temp display, it'll have a reference voltage to measure the temperature, if that's out then the reading is out too.