Board logo

LED problem - tintop
stevegough - 12/10/12 at 06:33 AM

Just put son's car through its annual, and it failed on a few points - one of them was the high-level brake light 'not working'. Well, it was working, but its only very dimly lit.
Taken it out, and connected it to a spare battery, and its just the same there - there are about 16 LEDs, about 4 of them are U/S, but it is very dim (bit like me!).

Any ideas please?

jossey - 12/10/12 at 07:01 AM

You could buy a 12v strip led off eBay and mount that in the case instead. They can be cut to length. And they are very Bright.

I would guess that it maybe quicker to find one at a scrap yard though n fit that to get the pass.

stevegough - 12/10/12 at 07:10 AM

quote:
Originally posted by jossey
You could buy a 12v strip led off eBay and mount that in the case instead. They can be cut to length. And they are very Bright.

I would guess that it maybe quicker to find one at a scrap yard though n fit that to get the pass.


Cheers, Jossey - getting a pass isn't really a problem, I checked with the MOT guy yesterday, and, as it is completely removed, it doesn't have to work! But I can't understand how it has dimmed the way it has?

madrallysport - 12/10/12 at 07:19 AM

I wasnt aware it was part of the test, i thought as long as the two rear brake lights where working thats all you needed. I've mot'd a few cars over the years without that extra high level one working. If its not there will that pass if you follow.

snowy2 - 12/10/12 at 08:06 AM

New MOT rules.......all brake lights must work. It may even mean that all leds in a strip must work.
dim lights something has gone high restance earth most likely or solder joints on live is poor/dry causing high restance.

stevegough - 12/10/12 at 08:25 AM

Thanks for all replies - I am thinking along the lines of a partial short - the car is damp inside ( passenger side floor is flooded ) I have now traced that problem - sunroof drainline is leaking into the sill!

nick205 - 12/10/12 at 09:54 AM

As you've tested the strip in isolation on a battery it suggests high resistance somewhere on the strip itself. Most likely corrosion or failing solder joints.

If you have a soldering kit you could retouch the joints very quickly and retest. Might solve the problem for free!


ETA...

SWMBOs tin top no. plate lights stopped working recently (just before MoT) and I traced it to a fractured wire between the body and tailgate. Easy (if laborious) fix by replacing a section of wire.

[Edited on 12/10/12 by nick205]

froggy - 12/10/12 at 02:11 PM

If you know it should work and it doesn't then it's a fail if it works even dimly and the other two work it's a pass and advise.