help with tail lights

This is for a 66' kombi
I have a base from a 69/70 ish and when I put it on strange things occur
When I use the breaks both lights go on(ie L and R) so thats cool
When I have the head lights on though and put the breaks on the new one goeas off and the old one does what is is spose to do?????

Have played round with it a bit but to no avail....help

Hard to tell, but could it be a bad earth?

if it is any help go to www.vintagebus.com and you should be able to down load the right wiring diagram.

99% of times when things like that happen it is a bad earth.
The extra current pushes up the voltage drop somewhere and stops the current flowing.
Either get a multi meter and try and trace it or just start cleaning up twerminal after terminal

The tail light works with out the earth leads on...but it doesnt seem to change even if I attach them. There is a terminal for the neg/earth but it dont work....the old one had holes drilled in it so the neg/earth lead touched the globe direct????

I had a similar thing on my beetle. I fixed it by bending the contacts that touched the globe in the suspect light, they weren't quite there.
It doesn't quite seem logical, but it fixed the problem, so I don't argue.:o
This was after checking every single earth and wire, and pulling out fist fulls of hair.

[Edited on 4-9-2003 by Kafer Lover]