£33.34 with delivery of £7.50 for the temperature sensor. Must be sent on a pallet. They were about £20 inc VAT from smart when I last bough one.
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3K @ 25°COriginally posted by tolsen View Post
cool, that's what I found too after checking. 3.3K is still ok to use too, it's not far out.
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Get an original outside sensor by Dealer, original are the best!
Dont go for upgrading, thats no good at all.
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An intelligent post worthy of being consigned to posterity.Originally posted by ossy View PostComment
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Oh dear. Right!Originally posted by ossy View Post
All smarts leave the factory with a standard OEM temperature sensor. IF they are that good, they wouldn't need changing.
But they do fail and they do need replacing.
If you can fix or make your own for less than £2 it means the OEM sensor would have to last at least 10 times longer.
They wouldn't.
From what I can make out is that water ingress gets into the plug and corrodes the connection. Making a replacement and fitting a decent AMP connection might outlive the car.Comment
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No corrosion on the two failed sensors I have in my possession. It is purely thermistor failure, possibly caused by impact with millions of Scottish midges or perhaps because cheap substandard thermistors were used during manufacture. Those I have sourced for repairing these outside temperature sensors are quality thermistors made by Panasonic. Expensive but should last many years.Originally posted by Evilution View PostComment
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One thing I didn't check but I'll have to see at a later date is if the original output is a linear or curved. Normally they are curved but you never know with smart.Comment
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Resistance temperature curve for our thermistor is logarithmic, not linear:
cedf1c04ed4f50c7768650d77a92557a.png, where 1f54d7129f43572d9ce00adc773a7b4c.png
B = Beta value = 3988 Kelvin, R0 = 3000 Ohm at reference temperature T0 (298K - 25C).
R is measured resistance of thermistor at temperature T (in Kelvin).Last edited by tolsen; 01-01-15, 11:02 AM.Comment
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Cool, saves me plotting my own graph.Comment
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That's a lot of messing about. I just took a handful of resistors of varying ohms, pushed them into the wiring connector and played the higher/lower game until the display shows 25 degrees. Then use higher and lower resistors to plot a graph if required.Comment
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There are many ways of skinning a cat but not easy working out Beta value etc from a non linear plot. The ultimate test will be when I fit the new thermistor. That is delayed until next week due to the Scots enjoying two days off after Hogmanay. RS' depot in Aberdeen does not open before Monday morning.Comment
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Have just replaced thermistor in two knackered outside temperature sensors. Tested by connecting to a Smart 450. Both read same temperature and also same as a borrowed original good working sensor. Appears to have quicker response time compared to the original sensor.
Replacing thermistor in these sensors is not for the clumpsy. The thermistor is very small and a certain amount of skill is required. Important to ensure distance from tip of thermistor to end of terminals is right. Should be 37.0 mm.
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But in the meantime, you can have an original and install them.
Because original is much better than any upgrade.
That is what a wise man told us every time.Comment
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This is not upgrade. It is called repair. Can't be anything wrong doing repairs. Sensor housings are still original, only the faulty thermistor has been replaced and now I have two fully working outside temperature sensors. Total repair cost only £1.39 per sensor which includes the bus return trip to RS Components in Aberdeen to collect two thermistors. Smart Stuff's charges £25.84 per sensor hence I have saved at least £48.90.Comment
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