Had a brake light blow yesterday so swappe..

Notice when side lights are in, the 2 x small independent bulbs light ok, BUT 2 of the larger 21W bulbs also light up, but just glow.

Are there Voltage droppers in the circuit as I would have expected that there would be a couple of 5W bulbs fitted for this job.

Tried a couple of 5W bulbs but these are even dimmer.

Also is there any way to get rear fog lamps to light at both sides rather than just offside ?

Check PowerBulbs - it should list all the bulbs for you

Had a brake light blow yesterday so swappe..

Notice when side lights are in, the 2 x small independent bulbs light ok, BUT 2 of the larger 21W bulbs also light up, but just glow.

Are there Voltage droppers in the circuit as I would have expected that there would be a couple of 5W bulbs fitted for this job.

Tried a couple of 5W bulbs but these are even dimmer.

Also is there any way to get rear fog lamps to light at both sides rather than just offside ?

I've read somewhere that if a rear bulb blows then the brake light on that side will glow on reduced power to compensate until the blown bulb is replaced.

As far as the fog light is concerned you will need a Vag-Com (VCDS) connection and then it's a five minute job. A dealer may not be able to do this on their system, but if they do, then they will probably charge. There are plenty of Vag-Com users on this forum.

Hope this helps

Mac

I was told by a towbar fitter that the Octavia uses 21w bulbs and then varies the voltage to give low-level light for the tail lights and brighter lights for the brake lights.

So it uses one bulb for both, but without using a 2-element bulb like some cars use.

Apparently it makes bypass-wiring for a towbar a little more complicated as it needs an electronic box to work out whether the tail lights or brake lights are on.

I haven't checked if any of this is true, just reporting what he said!

I was told by a towbar fitter that the Octavia uses 21w bulbs and then varies the voltage to give low-level light for the tail lights and brighter lights for the brake lights.

So it uses one bulb for both, but without using a 2-element bulb like some cars use.

Apparently it makes bypass-wiring for a towbar a little more complicated as it needs an electronic box to work out whether the tail lights or brake lights are on.

I haven't checked if any of this is true, just reporting what he said!

Correct, the Octavia has four (night) tail light bulbs.

Two are single filament 5W bulbs and are single function.

The other two are 21W single filament dual function bulbs, one is the brake light and night light (top) and the other is a fog light and night light (bottom).

The two 21W bulbs are not twin filament as you'd expect but single filament, power is increased when you brake or activate the fog light.

I don't know if the Octavia does it but on my old 2002 BMW 320d if a bulb blew any one of the other two tail lights would take over and compensate - all very clever!

Edited 15 August, 201015 yr by silver1011

Correct, the Octavia has four (night) tail light bulbs.

Two are single filament 5W bulbs and are single function.

The other two are 21W single filament dual function bulbs, one is the brake light and night light (top) and the other is a fog light and night light (bottom).

The two 21W bulbs are not twin filament as you'd expect but single filament, power is increased when you brake or activate the fog light.

I don't know if the Octavia does it but on my old 2002 BMW 320d if a bulb blew any one of the other two tail lights would take over and compensate - all very clever!

Many thanks to all, this is what I expected. Guess I'll have to find someone local with VAGcom gear. Seems daft not powering up the nearside for twin fog lights if all the wiring is there.

On my previous Passats, which weren't canbus controlled, I added a link cable from offside to nearside. On these I guess they did it to save on the cost of a bulb, but no extra cost on Octavia.

Whereabouts are you?

The bulb is already there.

Whereabouts are you?

Between Gloucester & Bristol.