External Temperature Sensor Failure?

[Scorchy]

Back in the colder days of 2014, I noticed that the external temperature reading was slightly lower than the ambient temperature - by a couple of degrees at first. Fast forward a few months and now at the end of May it reads circa -10, and it barely crept above 0 during the mini heatwave in the middle of the month. Also, the air-conditioning won't kick in, presumably because it thinks the external air temperature is plenty low enough.

I've read about the thermometer in the passenger wing mirror dying.

I'd be interested to know if anyone out there thinks this is the case, and if not, what else could cause this?

 

Any words of wisdom would be gratefully received.

Many thanks

Scott

[FridgemagnetC5]

I've had a couple of these go, both on XMs and C5s (I believe the sensor is the same spec for these two models, and I once successfully fitted an XM sensor to a C5). They should be more reliable than they are, given that it's just a simple thermistor that changes resistance with temperature.

 

I couldn't be bothered stripping down the door to find the sensor plug so I just took the glass off the wing mirror, cut the old sensor wires and soldered on the new sensor. I used a bit of heatshrink sleeving over the solder joints to prevent shorting/corrosion/errors due to leakage currents in damp weather. It doesn't matter which way round the two wires are attached as they aren't polarised.

[Scorchy]

Thanks Fridgemagnet!

 

I bought a new sensor from eBay yesterday from 'NeatCarParts' for £9.70 with free delivery, bargain! It arrived this morning so I'm just about to go out and put it in.

Is it just a case of prising off the mirror glass? I'm afraid of doing any damage as they're heated and auto dimming.

 

Thanks

Scott

[Scorchy]

Success! New sensor in without a hitch. No more 'risk of ice' warnings.