Lotus Elan

What should be the resistance of a heated rear screen?

PostPost by: John Larkin » Fri Sep 11, 2009 10:03 am

I'm trying to get my heated rear screen to work on my Elan S3 FHC --- it has never been wired up before. The electrical resistance across the screen measures 1860 ohms. This does not make sense to me. Resistance = (voltage squared divided by power), and assuming that the windows consumes about 150 watts then the resistance should be [(12 x 12)/150] ohms, i.e. about one ohm.

Advice greatly appreciated!

John Larkin.
1967 S3SE FHC, 1974 Rover P6B, 1949 Lancia Aprilia
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PostPost by: neilsjuke » Fri Sep 11, 2009 10:27 am

I think they use to draw around 6 to 8 amps from memory have you put a battary on it the resistance could well change after the heat as got the damp out ,would breath on them or put your face to the screen to see if it worked.
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PostPost by: types26/36 » Fri Sep 11, 2009 12:59 pm

John, I just measured the resistance across my element and it shows 13.9 ohms cold. It has never worked too well with some of the wires making practically no difference, in fact its pretty useless.
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