Is it possible to reset the Temperature Sensor?

[Phil303]

The sensor the gives the dash reading of the outside temp was unplugged to fit a new wiper motor.

Now the dash shows an outside temp of anything from -25 to -5. I've unplugged and replugged it in with no success. Is it possible to reset it somehow?

To be clear; the sensor I'm referring to is a white plastic prong about 5cm long that is fixed to the front of the scuttle, near the pollen filter towards the back-middle of the engine bay.

Thanks.

[David's8]

Well, damn me! I was replacing the wiper mechanism a few days back and wondered what that thing was!
The Laird was kind enough to have a spare wiper mechanism lying around which he let me have for liquid reimbursement (yet to be provided!) and as the sensor (as I now know) was attached i didnt bother transferring mine across. I gave him the defective wiper mechanism complete with sensor. So he has a spare if that is a potential source of the problem.
But your problem sounds more like a voltage stability issue than anything else due to moisture or bad (re) connection. The connector has a really strange and fiddly wire retainer which was a bugger to get back on.

[Dezzy]

Not sure on that one, i thought the outside temp sender was tucked up behind the front bumper

[Phil303]

From what I can gather there are two sensors; the bumper one as you pointed out and this one. The readings are taken from the lower reading of the two (or averaged between them - I can't remember) with engine temp taken into consideration.

There's been some debate as to whether they affect the engine running and/or aircon. Consensus is that the engine is unaffected by the reading from the scuttle sensor but the aircon might be

Could the voltage stability/connection issue be cured by a dose of WD40?

The plug is a pain: you have to pinch the top and bottom clips in really hard indeed before they release internally and free the plug. It also only fits one way round.

[Nick Jones]

There are two sensors as you say. One low down left of centre behind the bumper and one on the scuttle in the HVAC intake. They work together but it's far from clear how. I wasted ages messing about with these as my display was giving stupidly low readings. Changed both sensors (at different times). When I first swapped the bumper one it seemed to do the trick - for two days, then reverted. Both old and new sensors measured the same. In the end I discovered that leaving the scuttle one disconnected produces a sensible (though possibly not dead accurate) reading.

The HVAC also uses this reading - what caused my interest as it was preventing the AC from working as the car though it was -5ºC when it was actually >20ºC.

Good luck with it and if you do beat it I'd be very interested to hear how you did it!

Cheers

Nick

[47p2]

Sounds like you haven't pushed the connection back together properly. The temperature sensor usually throws up silly numbers if disconnected and not reconnected which is what yours seems to be doing. Try unplugging it and plugging it in again

[Phil303]

Unplugged it again and plug it back together, left it overnight and it fixed itself.

[47p2]

[Norretal]

Originally Posted by 47p2

Sounds like you haven't pushed the connection back together properly. The temperature sensor usually throws up silly numbers if disconnected and not reconnected which is what yours seems to be doing. Try unplugging it and plugging it in again

This bloke knows his stuff

[HPsauce]

Intriguing, I had a very similar problem on my trusty old Ford Focus a few years ago.
The external temp sensor on that is behind the main impact beam centre of the front bumper, bit of a PITA to get at.
Silly numbers appearing, but just unplugging and reconnecting "firmly" a few times sorted it. It did take a while to reset though, wasn't immediate.