I have changed the rear brake bulb on both sides, and I have noticed that the rear 'headlight' bulb also comes on but not as bright. Does that make sense? Its the bulb at the bottom of the 4 cluster.

Any idea's? The bulb is the same as the old ones.

Edited 30 April, 201313 yr by Sippo

Having a 'look' through the forum, am I correct in thinking that the bulb needs to be 21v 4w? I bought 21v 5w from halfords according to their book. Can I take them back stating false information?

certainly worth a go.

their book is wrong for most bulbs in the octavia including the HID bulbs

The Octavia rear lights are very sensitive to incorrect bulbs.

You do indeed need a 21W/4W and not the 21W/5W Halfords incorrectly tell you to use.

It seems a little strange that the fog light bulb also illuminates at a reduced intensity when the brake pedal is pressed, this sounds more like an earthing issue.

It should be worth noting that the brake and fog light bulbs double up as tail or night lights (hence the twin / 4W filament*). Could it be that you had the tail lights turned on when testing the brake lights?

*excludes the estate. The estate uses a single filament 21W bulb to perform both the brake/tail and fog/tail functions by controlling the bulb intensity via the CANBUS.

Edited 30 April, 201313 yr by silver1011

Edited 30 April, 201313 yr by silver1011

Definitely didn't have tail lights on. Back to halfords tomorrow then!