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I'm trying to identify a part in a circuit that has next to zero information out there on the web other than the wiring diagram itself direct from BMW's NEWTIS.

I'm trying to fathom out what the circled component is. I think it's a PTC, with the theta symbol (ϑ) meaning the resistance increases with the temperature but was hoping someone would recognise it and be able to give me clarification or correction.

enter image description here

JYelton
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IAmOrion
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    I think NTCs are more common as thermal sensors than PTCs. Also the wires are called *NTC*FA and HZFA. – Oskar Skog Oct 18 '22 at 17:35
  • Theta just means temperature, I don't believe it corresponds to PTC. See also https://electronics.stackexchange.com/a/581636/2028 – JYelton Oct 18 '22 at 17:35
  • @OskarSkog - well spotted, I hadn't twigged that! – IAmOrion Oct 18 '22 at 17:48
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    At least on this Z4 you don’t have to pay BMW a subscription to use your heated seats… https://www.thedrive.com/news/bmw-responds-to-fury-over-heated-seats-subscription-fee – hacktastical Oct 18 '22 at 17:49
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    Not a BMW, but when I retrofitted a Recaro seat, it was a big standard 10k NTC in it for temperature read back. – winny Oct 18 '22 at 17:56
  • Haha @hacktastical, like oscilloscope manufacturers do .. – RemyHx Oct 18 '22 at 20:11

1 Answers1

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The symbol just means it is a device with temperature coefficient.

There is no indication in the symbol itself to which direction the coefficient is, and the symbols that would indicate the coefficient direction are missing.

However, it seems that it is a component used to measure temperature, and generally an NTC is more useful for that. PTCs are generally more useful for other purposes.

Also the text on the diagram says NTC, so there is very little indication it would be anything else than an NTC.

ocrdu
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Justme
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