Ambient air temperature sensor

[shottdi]

Hi. I have a problem with the ambient air temperature reading on the dash display of my 2007 Jetta TDI Sport. Recently the temperature on the display went down to minus 10 degrees. After a while the temperature steadily rose until it was reading the correct outside temperature of 15 degrees. Next day it went down to minus 12 degrees. This has happened numerous times, so I fitted a new ambient air temperature sensor, which is located just behind the radiator grille, at the front of the car. Still no luck. The temperature is now reading minus 16 degrees. Does anyone have any idea what may be causing this fault? Thanks for any help.

[Crasher]

I would put it on the computer and look at the values to see if they correspond with those shown in the display, if they don’t it probably has a faulty dash but I have not come across this problem before.

[shottdi]

OK, thanks for the prompt reply, Crasher. I've had another look at the sensor again, after reading on another forum that it could be due to water ingress in the plug attached to the sensor. I removed the plug, sprayed it with solvent cleaner and then dried it for about 10 minutes with some gentle heat from a heat gun. I sealed the end of the plug where the cables enter it with some silicone sealer, and so far it is working OK. Readings on the display now match the outside air temperature, so fingers crossed! Thanks again for your advice.

[Hyper-Remaps]

water ingress.. good fix, glad you got it sorted, i did experiance this on my b5 once, and it was down to a poor battery, but not as cold as yours.. brrrrrr.. lol.

[sharc]

I know this is a really old thread but the same thing just happened to me today, and I am pretty sure it's to do with water because it happened just after I drove through a deep puddle. The temperature display went down to -50.0! Because the Climate Control is partially controlled by the ambient temperature, all of a sudden it went into overdrive trying to warm the car up! so it looks like I'm going to have to dry out my sensor also.

[Crasher]

This was all three years ago, perhaps you should start a new thread?