Simon Davis Posted January 2, 2016 Share Posted January 2, 2016 Following a jump start for a flat battery, (son left lights on), the outside air temperature is now shown as -50 degrees. It varies as the actual air temperature changes, so is working to a degree. (Sorry about the pun). Is this likely to be a temporary fault or will the sensor be fried? If so, where is it? Any advice welcome. The car is a 2008 1.8 TDi Zetec Estate. Simon Quote Link to comment Share on other sites More sharing options...
dezwez Posted January 2, 2016 Share Posted January 2, 2016 it should go back Quote Link to comment Share on other sites More sharing options...
WES180 Posted January 2, 2016 Share Posted January 2, 2016 Is that minus 50 or has it just switched back to Fahrenheit rather than Celsius? 1 Quote Link to comment Share on other sites More sharing options...
Simon Davis Posted January 2, 2016 Author Share Posted January 2, 2016 No, it's still set to Celcius Quote Link to comment Share on other sites More sharing options...
WES180 Posted January 2, 2016 Share Posted January 2, 2016 Have you tried switching it to Fahrenheit then back to Celsius to see if it recalibrates? Worth a try. 1 Quote Link to comment Share on other sites More sharing options...
Simon Davis Posted January 2, 2016 Author Share Posted January 2, 2016 Thanks for the suggestion. Unfortunately, it didn't solve it. I forgot to mention that the low temperature "snowflake" symbol is also displayed, as would be expected if the temperature shown were correct. Quote Link to comment Share on other sites More sharing options...
WES180 Posted January 2, 2016 Share Posted January 2, 2016 I would disconnect the battery for 30 mins and then try again. It solves a lot of little niggles! As said above though it will probably sort itself over a bit of time but it is annoying when things are not right! Quote Link to comment Share on other sites More sharing options...
dezwez Posted January 2, 2016 Share Posted January 2, 2016 try disconnecting the battery for 30 mins Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted January 2, 2016 Share Posted January 2, 2016 Following a jump start for a flat battery, (son left lights on), the outside air temperature is now shown as -50 degrees. It varies as the actual air temperature changes, so is working to a degree. (Sorry about the pun). Is this likely to be a temporary fault or will the sensor be fried? If so, where is it? Any advice welcome. The car is a 2008 1.8 TDi Zetec Estate. Simon Where was the negative lead from the donor battery connected to on the other car ? 1 Quote Link to comment Share on other sites More sharing options...
WES180 Posted January 2, 2016 Share Posted January 2, 2016 try disconnecting the battery for 30 mins Good idea Dez, im sure i just said that though!;) 1 Quote Link to comment Share on other sites More sharing options...
dezwez Posted January 2, 2016 Share Posted January 2, 2016 that two of us then :) Quote Link to comment Share on other sites More sharing options...
WES180 Posted January 2, 2016 Share Posted January 2, 2016 Where was the negative lead from the donor battery connected to on the other car ?I know what youre going to say Mark, ive always done it battery to battery over the years. Just for clarity what damage can it do like that on modern cars as opposed to on an earth point? Does it cause too much of an electrical spike or something? Quote Link to comment Share on other sites More sharing options...
Simon Davis Posted January 2, 2016 Author Share Posted January 2, 2016 battery negative from donor car was connected to the lifting eye on top of the engine Quote Link to comment Share on other sites More sharing options...
iantt Posted January 2, 2016 Share Posted January 2, 2016 Its nothing to worry about, seen it a few times after battery disconnected, just leave battery connected, and use the car as normal, it will come down to the corect temperature eventually. . 4 Quote Link to comment Share on other sites More sharing options...
WES180 Posted January 2, 2016 Share Posted January 2, 2016 Its nothing to worry about, seen it a few times after battery disconnected, just leave battery connected, and use the car as normal, it will come down to the corect temperature eventually. .Well done Ian, its good to have proper mechanics (or is that technician's?) on here to give expert advice rather than our guess work.To be honest I didnt actually know the reasoning behind not jumping battery to battery, good old Google provided this - The reason that it is better to make the connection to a bare metal part of the car rather than directly to the battery is to minimise the risk from sparks around the battery itself which in extreme situations could lead to an explosion (due to the ignition of hydrogen released from the battery when it is charging). Although exploding batteries might be very rare the consequences are horrific (as they are filled with acid) if you do connect directly to the negative pole of the dead battery you should wear eye protection - just in case you are the 'one in a million'. 2 Quote Link to comment Share on other sites More sharing options...
Simon Davis Posted January 2, 2016 Author Share Posted January 2, 2016 Thanks iantt and everyone else. I'll leave it and see what happens; sounds like all will be well. Regards Simon 2 Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted January 2, 2016 Share Posted January 2, 2016 I know what youre going to say Mark, ive always done it battery to battery over the years. Just for clarity what damage can it do like that on modern cars as opposed to on an earth point? Does it cause too much of an electrical spike or something? In short Wez yes it can. Every handbook I've ever read, the A.A. & R.A.C. et al recommend connecting the negative lead to the body earth & the primary reason is to minimise ignition & consequent explosion & secondly this method minimises power losses through the dead car's earthing circuit so will ensure a better chance of a successful jump start. There is also a body of thought that incorrect connection is responsible for '' frying '' some delicate circuits & that opinion is somewhat borne out on Forums where people say after jump starting my xxx no longer works etc Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted January 2, 2016 Share Posted January 2, 2016 Well done Ian, its good to have proper mechanics (or is that technician's?) on here to give expert advice rather than our guess work. To be honest I didnt actually know the reasoning behind not jumping battery to battery, good old Google provided this - The reason that it is better to make the connection to a bare metal part of the car rather than directly to the battery is to minimise the risk from sparks around the battery itself which in extreme situations could lead to an explosion (due to the ignition of hydrogen released from the battery when it is charging). Although exploding batteries might be very rare the consequences are horrific (as they are filled with acid) if you do connect directly to the negative pole of the dead battery you should wear eye protection - just in case you are the 'one in a million'. Your google search beat me to it Wez - same answer though :) 1 Quote Link to comment Share on other sites More sharing options...
Simon Davis Posted January 2, 2016 Author Share Posted January 2, 2016 Update - after a rest, the system is now working properly, i.e. we now have 9 degrees, not -50. Thanks to all who replied; it's great to be able to access such a breadth of information and advice. Simon 3 Quote Link to comment Share on other sites More sharing options...
iantt Posted January 2, 2016 Share Posted January 2, 2016 Thats good . Quote Link to comment Share on other sites More sharing options...
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