Hello everyone, I’ve got an issue with my third brake light - it doesn’t work… and I can’t seem to find any replacements out there. The primary brake lights both work as they should.
Suspect it could be the wiring or the unit itself, but waiting for tomorrow to check with a multimeter. Has anyone had this problem before or any advice to sort?
Thanks
Check the wires which pass behind the plastic wall/liner at the back of the boot, before entering into the third brake light . Sometimes these break?
I only came across these because I broke into that circuit to fit a plug to allow optional connection of an additional third brake light which I use if I have luggage on the boot rack.
The luggage blocks the third brake light, so my additional light is simply fastened to the edge of the rack, below the luggage.
I’ve nothing to add on diagnosing the issue, other than the multi meter. However, if you need to take the lamp out, you’ll need a set of long reach sockets. I don’t recall the size (maybe 10mm). Slide a socket over the end of the trim clip from inside the boot, to compress the wings and make it easier to get it off.
And it’s a Sealed unit by the way, so you can’t do anything with it when it’s off.
Mine stopped working a couple of years ago and it was traced to a broken wire in the loom under the rear deck.
Nice one, thanks all! I took the rear boot panel off on Tuesday and couldn’t see any visible wear/damage to the wires immediately visible, but weather’s been terrible, so not done any deeper investigation since. Will report back once I’ve got the multimeter on it.
Hi everyone, as a way of an update and sense check
Got the multimeter on it and was getting 0v and no continuity at the third brake light connector, so worked back and the connector directly before it was getting a solid 12v as it should.
Here’s where I could do with some sense checking…
The connector that the third brake light in my car was connected into seems (to me) to be a circuit to feed an unused and unneeded (for me) accessory plug to feed the boot rack brake light - like seen in this thread.
The third brake light was connected to this circuit, so I’ve unplugged it and put it directly into the previous connector that’s getting voltage. And huzzah, the brake light is working as it should again.
Above: the original set up, the conenctor the third brake light was going into on the bottom right.
Above: what I’ve done, connecting the third brake light directly into the previous connection and essentially disconnecting the accessory plug circuit.
To me, it seems there’s a short/break in the wiring to the accessory plug and all I’ve done is re-establish the circuit as it should have been originally - disconnecting the luggage rack wiring harness essentially.
