New Tail Lights Problem (Earth Wire)

[Njck]

Hey hey, I just got some new tail lights, not made by Ford, but I am having trouble installing them, thought it was a simple plug n play since the rears aren't that hard of a swap. the right one is fine, but when the left one is connected it makes everything reversed, so my brake lights are dim and my sides are bright, as well as having the boot brake light on continuously when my sides are on, which is quite dangerous since people won't see that I'm breaking. Contacted the seller and he said As for your problem can you check the earths for the lights. Sounds like an earth problem. Maybe it was disturbed when you fitted them.

If not let us know. I will ask supplier monday of they have any other idea's. I don't know what I have possibly disturbed since it is all wired and ready, any help at all is appreciated.

It's a mk6 5 door btw

Thanks!

Nick