Boot light, switch, third brake light problems Topic is solved

[S40volvo2007]

10/19 = Third Brake Light.

ThirdBrakeLight.png

what voltage should it read 12v or lower?

[S40volvo2007]

Ground pin #5 on the third brake light, see if it starts working.

Take some pictures of the connector on the third brake light. I cannot find anything for pins 2 - 4 but it looks like there should be a power line.

Had a closer look and it seems that third brake light is working when braking but is very dim you can see it but only just. There is a green connector with a yellow wire and a black wire.

[RickHaleParker]

Had a closer look and it seems that third brake light is working when braking but is very dim you can see it but only just. There is a green connector with a yellow wire and a black wire.

Yellow (#1) is the power, measure the voltage.
Black (#5) is the ground, run a second ground to #5 and see if it brightens up.

Check the CEM electrical connectors. Make sure they are clean and in good condition. Even a thin layer of tarnish can cause problems.

[S40volvo2007]

Just an update, ground was fine but no luck with the third brake light, which pointed me to think I have a faulty led, so I grabbed a second hand one and installed, works perfect. Thanks for your help, that concludes my electrical issues with this great car.