Page 1 of 1

ABS & LED replacement bulbs

Posted: Thu Nov 25, 2010 7:36 pm
by Jaws
Recently fitted some LED tail/brake light bulbs and soon noticed that the ABS warning light kept coming on. A quick search pointed to a couple of threads reporting the same problem but no solution apart from going back to standard bulbs.

So two questions really; if the ABS warning light is on does this necessarily mean it's not working? ( I'm guessing 'yes') and is there any way to cure this without going back to the standard bulbs?

Thanks for any input!

Re: ABS & LED replacement bulbs

Posted: Thu Nov 25, 2010 8:39 pm
by g8dhe
This is only a guess, but LED's don't draw any current until the voltage across them exceeds about 2-3 volts. Now the ABS unit monitors the lamps and I suspect it expects to see a small current drawn thru the lamps at a low voltage - not sufficent to light them however. So you could try connecting a small 5W bulb across the brake lights so that the ABS circuit can see the expected current being drawn - the lamp need not be visible, it won't even light when the ABS unit is checking, but it will come on when the brakes are applied of course.

Re: ABS & LED replacement bulbs

Posted: Thu Nov 25, 2010 10:21 pm
by Jaws
Thanks for that. Actually, now you come to mention it, I notice a dim glow from the LEDs when the ignition is on. Presumably the check you refer to.

I had considered another bulb in parallel as you suggest, but wondered if there was a more elegant solution.