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LED tail lights not working when braking.

Posted: Mon Oct 20, 2014 8:39 pm
by Bwar
Alright, so I replaced my rear tail lights and front lights with the Alteeze cluster and DRL clusters respectively, and had no dramas whatsoever.

I got defected for my HIDs, so I replaced the entire cluster for ease, to pass the inspection, and that's when i started having problems.

It started with the very occasional traction control being turned off with a "service required" comming up on the dash, which I narrowed down to one of the parkers being blown on the stock cluster.

Today I replaced the DRL cluster, and the first thing I noticed was that the brake lights weren't working. The lights come on when I turn on my parkers/DRLs and headlights, but not when I'm braking. The problem (seemed to) correct itself after about 15 minutes.

The cruise control (and presumable the traction control) was still not functioning correctly, so I installed some load resistors, to see if that would fix the issue, and now not only do I not have cruise control, my brake lights will flicker on once every now and again, and then cease to work, outside having the parkers on.

I'm completely stumped. It can't be a fuse, because they do flicker on occasionally when I press the brake, and it can't be a miss wiring, because they function in line with the parkers.

Anyone have any advice? It's a pretty big safety issue, so I'm not really confident to drive with it like this.

Posted: Mon Oct 20, 2014 9:01 pm
by Speedie
Sounds like there is not enough load on the circuit, If you got the right resistors then you shouldn't be having problems.

Posted: Mon Oct 20, 2014 9:31 pm
by Bwar
I used 50w 6 ohm resistors, does that sound about right?

Posted: Tue Oct 21, 2014 6:13 am
by Zaphod
First step: chuck the original lights back in, see if the problem goes away...

Posted: Tue Oct 21, 2014 7:19 am
by Kal777
resistors should be 18-21W i would have thought, your wanting to imitate the missing globe that the now less demanding LED's have replaced. CAMBUS looks for a load close to that of the expected globe on each of the circuits, in the case of brake and indicators this globe is 21W

Posted: Tue Oct 21, 2014 1:16 pm
by Bwar
Alright, so I found some of the problem.

One of the resistors had come loose, so the signal cable for the lights was grounding on the chassis, so that's fixed.

The lights are now intermittantly working, to the tune of: they work fine twice, then they flash and go out, then they don't work a couple of times, then they work fine a couple of times, etc etc.

Should I start with a smaller load resistor?

Posted: Tue Oct 21, 2014 2:17 pm
by Bwar
I plugged in the OEM headlights, also, and hte problem persists. Took it for a drive, however, and hte cruise control seems to be working perfectly, so i think that rules out the resistor being wrong?

How does the lancer detect that the brake is being applied then send the signal to the lights? Is it digital? A switch near the pedal that could be fused?

Posted: Tue Oct 21, 2014 6:02 pm
by Zaphod
The wattage refers to the amount of power the resistors can handle before overheating; the resistance value may be too low - try running two in series temporarily to increase the load and see if they behave better.

Insufficient load on the circuit can be interpreted as a short circuit, which can cause flicker/shutdown. Also a 'low power' load resistor can overheat, greatly increasing the resistance in the circuit causing drop in current flow, preventing the LEDs from turning on once it's gotten sufficiently hot. You'll find a balance fairly easily (assuming the light assembly themselves aren't faulty); flick the supplier an email and see if they have any suggestions...


Again, isolate different parts: work at one end at a time - if you're testing the headlights, put the OEM tail lights in and vice-versa.

Posted: Tue Oct 21, 2014 10:33 pm
by Bwar
Thanks for the info Martin!

I saw in an Ofey post he was shipping them with 180 ohm resistors at one point? As I will have to purchase some more resistors tomorrow anyway, I might start there, and get a few, Jaycar seem to have a very good selection. I hope they come all ready to be wired in :-\

I'm going ot have to sort out some way to repair the cables too, only so many times you can cut the wires and retry a different configuration before they are rooted. Might have to get handy with a soldering iron in the next 10 hours, I spose.

Posted: Tue Oct 21, 2014 11:08 pm
by Bwar
Also, just to clarify, there are three wires running into the brake lights, a black (presumably negative), a solid green, and a green w/ white stripe. I assumed the solid green was positive (no multimeter) and felt warmth from the heatsink when the parkers were on, so I assumed I had it right?

Posted: Wed Oct 22, 2014 5:52 am
by Zaphod
I don't honestly know - I've only ever dealt with 'plug' & play' assemblies...

There's a copy of the service manual on this site, have a look: http://clubcj.net/viewtopic.php?t=8528

It may help?


Cheers.

Posted: Wed Oct 22, 2014 12:42 pm
by Bwar
alright, so i've disocovered it is not a wiring issue at the back of hte car, and it's not a resitor problem, and the cluster is fine

if i introduce 12v into the solid green wire, with 12v running into the green w/ white, i get brake lights

when i depress the brake, the green wire only gets .3v

when i depress the brake, the fuse is getting 14v.

the problem is womewhere between the fuse and the wiring harness that runs ot the lights

Posted: Wed Oct 22, 2014 1:34 pm
by Speedie

Posted: Wed Oct 22, 2014 2:25 pm
by Bwar
I haven't got much experience for reading circuit diagrams, but from what i could decipher, that isn't the same diagram as my car. I was trying to check fuses and the like off of it, an what i've got seems ot be different..