Scottish Elises

In my never ending quest to replace every bulb with an LED, I bought ones to replace the reversing bulb and the rear fog. Now according to elises.co.uk they're the same type:

•Rear fog lamp 21W SCC BA15s
•Reversing lamp 21W SCC BA15s

So I bought a super bright white and a red, identical types from the same place. The reversing works fine, the fog doesn't at all. It did before and still does with the old bulb.

Any ideas?

LED are polarity sensitive, try turning it round I'd have bought 2 white one too... Fog has a red lens anyway so will be brighter with a white bulb?

Cheers Mark I'll try that tomorrow. I bought a spare white as well so they you go

Still no joy, even with the white bulb. http://wiki.seloc.org/a/Bulbs This says that they might actually be different?

Can you test it with a 12v supply?

It's still working with the original bulb in place, that's why I presumed it was the bulb replacements that were wrong?