Third brake light (LED) test

Question

I have a 2008 Honda Civic and the 3rd brake light is having an issue. It seems in the morning (first cold start) it works when I depress the brake (I can see it light up the rear window). But after a few pumps, the light stops working. It is an LED array and I always thought that those should last way longer than regular bulbs, as in fact, I have not even replaced any tail lights just having an issue with this 3rd break light.

Before I go and spend $120-$200 for a replace and install, is there a way to see if something is causing a connection issue? Everything that I can reach seems to be attached and like I said, on first start up and for the first few bumps on the brake, it lights up.

I need this to work to pass my next vehicle inspection here in Mass, USA.

Any first places to look or steps to trouble shoot that I can take?

Answer 1

The fact that the light bar lights up means that it works. If the fault is consistent, I'd be more tempted to look for the fault at the brake pedal - where the switch for the light is.

As your existing brake lights work correctly, next step is to see whether they use the same switch, as per @Brian's comment. It may be that the LED bar has been wired in completely independently of the original lights.

Answer 2

After much deliberation on going to repair shop, I figured I would at least poke around as it could not make anything worse.

Here was the problem. The negative terminal wire soldering point was loose.

I fixed it this way:

1. Unplug the LED array. (Pictures to come) Video of removal process here on youtube

2. Remove the rear plastic shroud(with a few upward slaps) by folding down the rear seats and slap the edge of the shroud up. Slide the shroud forward as there are tabs that the part nearest the window slide into(and is then held in by the clips you released by "slapping up").

3. Unscrew the LED mount and the round plastic speaker rim(the rim looks to be like a gasket, not a part of the speaker.)
4. remove the LED array from the rear shroud. I found my issue by plugging in the light and tapping around. It would flicker so I knew something was loose. After pressing the neg terminal solder spot, I could see that although it looked solid, it was not.
5. Heated up the solder iron, tapped a little solder on there and tested. The LEDs worked! Keeping the pedal depressed, I simulated bumps and the like while it was plugged in, no flicker, all solid.

Reassembled in reverse of above.

This saved me over $200.00 in parts and labor.

Answer 3

A good service manual will have extensive wiring diagrams and possibly troubleshooting procedures and connector locations. With that and a multimeter, you can easily track the problem down. I prefer factory service manuals over Haynes / Chilton / etc, but they're not cheap. Looks like the one you would need would be $150 from Helm.

If you can verify the light is getting power but not illuminating, you can try replacing it. If it's not getting power when it should, I'd suspect a wiring or switch problem. I'd tend to agree with Rory, though, in that the switch is the top suspect. To confirm / deny that hypothesis, you'd need to check the wiring going into and out of the switch while you toggle it. That's about as far as you can go without some wiring diagrams. If the switch is fine, you'll need to probe the rest of the wiring between the switch and the light. This is where the factory manual would come in handy, showing you how the wiring is routed, what connectors there might be that you could probe in between the switch and the light and where they're located, etc.

You might check the fuse, make sure that it's not loose and the terminals / blades are not dirty / corroded.