Avensis T25 Estate Led Rear Lights

[Duggerz]

Hi All,

I'm in the process of replacing bulbs with LED as the incandescent ones fail, and no problems with the single filament bulbs such as side lights, headlights or reverse/fog, but the stop and tail LEDs available do not seems to be a drop in replacement because when fitted the tail will not work but the brake will. I read that a resistor may need to be added but I don't see how adding a resistor will turn on a bulb. I do see that one may be needed to dim a bulb or to fool an indicator flasher unit that the bulbs are there.

In the T25 the stop and tail are the regular 21/5W dual filament bulbs which are 2 separate circuits with a common ground, the bulb body. This is the second set of LEDs I've bought that don't work on the tail circuit, so at this point I'm assuming I must be missing something. If anyone can point me in the right direction I'd be very grateful!

Cheers

Ian

[gazza1286]

Led bulbs only work with the current flowing in one direction. Have you tried reversing the polarity on the one which doesn't work?

[Duggerz]

Thanks for your response, you're spot on, and I hadn't thought that the polarity would be wrong. Problem is how to reverse the polarity on one circuit when both the stop and tail share a common ground? When I wire up to a test circuit I can get either stop or tail to illuminate just by touching the wire to the appropriate pin while keeping the ground common, and they do both work, so I am at a loss to explain how the Avensis could be wired incorrectly given the common ground needed. Having said that my autoelectrical skills aren't the best!

[Duggerz]

I had a rethink about this, and checked the connections. Seems that I have a fault there somewhere as wiggling the connector does allow the LED to light intermittently. So the bulbs are fine after all! Thanks for your help.