Yaris Rear Driving Lights Problem

[ap222]

Hi all, I'm new to this forum, need help with a problem with my 2003 Yaris.

There seems to be a short circuit in the RHS rear light unit. This is what happens:

At night with the driving lights switched on, both rear driving lights are fine.

However, whenever the brakes are activated, the brake lights come on but the RHS driving light deactivates momentarily. When the brake pedal is released, the RHS driving light comes back on. The LHS lights are unaffected.

I've looked at the light connector, cleaned it, but its all good. Could this be a problem with the bulb?

Any help appreciated.

regards
AP