interesting lighting fault! please help

got a 1989 defender 90 with some wierd and wonderfull lighting issues.

right heres the break down of the symptoms.
when indicating right the right rear indicater is dim.
when the break peddle is pressed the brake light flashes and indicator doesnt.
when headlights are on indicator doesnt flash but brake light does.
when fog light is swithced on fog light flashes and indicator is dim.

ive got as far as determining this is a short circuit. (line to line rather than to earth) how ever i was wondering if any one had had similar symptoms and could point me in the right direction (ie possible relay/swith problems or cable chaffing hot spots)
any help would be a start
ta

Bad earth at a guess.

Hmm..indicator seems to be common theme here, i'm guessing earth too.

Take the lens off and check the little copper contacts where the bulb sits and the screw that holds it on. These get brittle or (forgot english word) green chemical reaction thingy that prevents a good circuit.

bad earths can cause allsorts of wierd problems..its a case of testing all earths and connections im afraid

A good start is to get a piece of wire and earth one end then start by giving a direct earth to the indicator at the back and seeing what the out come is. it is possible that all the rear lights you mention have a common earth to the body that has corroded and just needs cleaning up or cables reterminating. Failing that check any trailer sockets you may have for mud/water. bad earths cause mayhem but are easily cured.
I hope this helps and solves your problems.

i think its a combination of the common earth that top-cat said and the indicator earth its self. but the common earth is behind a panel that i cant get off without taking all the spare wheel rack off. i think it may have to wait till tomorrow. ill let you know the out come.
thanks for your help so far

Definitely an earthing problem.

Tis an earth fault.

it is an earth fault.
despite saying id do it tomorow it wer bugging me so i went and had a crack at it. common earth between the three that disappear in to the chassis. no idea where it will emerge so ill splice it in to an earth i know is good.
only problem was when taking it apart the indicator bulb holder and all the connections just dissintigrated.
bloody pain ive had nowt but bother wi the earths on this thing