Mk3 Yaris water ingress

[JimboCycling]

I'm getting water in the car around the right rear. It gets most noticeable on the underside of the back right seat but we've had water in the boot including on the plastic trim on that side between the tail light and the back of the back seats. 

Other things online have pointed me to the seal around the rear light. It's a bit brittle but not totally perished, small hole around one screw, so is that likely to be it? Would the fix be to just replace the whole light fitting? Any other ideas? 

Thanks 

 

[TonyHSD]

You need to take both rear lights out of the car. Clean them very well from dust and debris, do same thorough clean on the body work these lights fit in, and replace seals with new original. Put back lights and secure, do not over tighten the bolts. If you have no new seals , after everything it’s perfectly clean you can apply silicone sealant or similar onto the existing seals both sides and put the lights back. This will stop any water ingress, however in the future if you need to remove the lights might be very difficult. 👍