DS3 Brake light fault

Andy89 · Oct 25, 2020

Hi guys,

Got a Citroen DS3 with a rather strange fault. The tail light brake lights (Left and right) never work with the brake pedal, however the actual bulbs are fine because they light up when the lights are switched on (but the brake light always stay on). Checked the brake switch and it meters fine and the strange thing is the centre light on the rear glass works with the pedal as expected.

So the bulbs work, the brake switch works, fuses are fine and wiring to the brake bulbs must be fine because they do work only with the lights switched on.

Any ideas please? Any input would be appreciated as I'm baffled! Cheers

telectrix · Oct 25, 2020

auto wiring has never been a strong point with the froggies. ( sorry, not very helpful ).

Andy89 · Oct 25, 2020

It's been great mechanically but not electrically I must admit

telectrix · Oct 25, 2020

sounds as though been supplied from light circuit, but that would not explain the supplementary light working normally. time to start tracing the wiring back from the brake lights to switch then further back.

Andy89 · Oct 25, 2020

telectrix said:
sounds as though been supplied from light circuit, but that would not explain the supplementary light working normally. time to start tracing the wiring back from the brake lights to switch then further back.

I can't even find a wiring diagram anywhere. Is there a chance that the stalk control itself could be faulty?

ruston · Oct 25, 2020

The usual culprit is the harness trapped and shorted where it comes through the tailgate , if it has one. Another culprit is the lamp holders , especially on dual filament holders where they make contact with both filaments cause by being incorrectly fitted or wrong lamps, or just plain worn out. I would check the harness first though , and check for water ingress and corrosion.