Third brake light does not work

[M3GT]

The third brake light on the trunk lid does not work on my 05 Mazda3 sedan. I replaced the bulb (I got it from the dealer to ensure it's the right one) but still no luck. The tail brake lights work.

I'm trying to figure out which fuse is this bulb on, but I can't find it in the tables listed in the manual.
Does anyone know which fuse I should check?
If the fuse is not the issue, what else could it be?

[Noisy Crow]

All three brake lights are powered from the same place.... although there is a separate wire run from the PJB to each. Have you tried unplugging the bulb adapter and checking the voltage with a multimeter?

[M3GT]

I though the 3rd brake light is on different fuse since I noticed that the left and right tailights are (for fault tolerance reasons I believe). I haven't tried to check the voltage; I thought it would be much easier to confirm the fuse is OK first, but if this fails, I will. I thought I would try replacing the socket as well if it's not too expensive.

[eqlso]

After you open the trunk, check the rubber hose protecting the wires on the left side near the damper. Pull open the hose, and see if any of those wires are cut.

[M3GT]

After you open the trunk, check the rubber hose protecting the wires on the left side near the damper. Pull open the hose, and see if any of those wires are cut.

Thanks for the hint. I'll check them out. What leads you to believe this would be a potential cause?

[Noisy Crow]

I though the 3rd brake light is on different fuse since I noticed that the left and right tailights are (for fault tolerance reasons I believe). I haven't tried to check the voltage; I thought it would be much easier to confirm the fuse is OK first, but if this fails, I will. I thought I would try replacing the socket as well if it's not too expensive.

Well the Mazda wiring schematic thinks they are working off of the same fuse...... along with the horn...

Before you spend money on parts grab a multimeter (5-10 bucks at Canadian Tire!) and check the voltage.

[M3GT]

Well the Mazda wiring schematic thinks they are working off of the same fuse...... along with the horn...

Before you spend money on parts grab a multimeter (5-10 bucks at Canadian Tire!) and check the voltage.

OK. In this case, the fuse is OK because the horn is working. I'll check the voltage. Thanks for the advice.

[M3GT]

After you open the trunk, check the rubber hose protecting the wires on the left side near the damper. Pull open the hose, and see if any of those wires are cut.

Thank you sir! Your were spot on. One wire was cut and two other wires had the insulation cut. I used a wire connector to fix the damaged wire and some electrical tape for the other two. I don't think the fix will last so I'll probably have to get a new harness soon ($96+tax for the part and one hour labour or just over $200).

[eqlso]

Happened to me too, but it was one wire at a time. Not sure what caused it to cut too, since it was a very clean cut across. I just soldered some extra wire on, taped it all up, and it hasn't happened again.