defender electrical problem

[westy 90]

Got a problem on my defender 90 300tdi some times when driving with the lights on and the dash board lights go really dim and start flickering so much it looks they are not on. then after a couple of seconds they come back to life then this repeats a few times then stops. Also the stereo cuts in and out and when i indercate it cuts the stereo out then comes back on a few seconds later. Is this a bad earth some were or more don't really no were to start looking because of the amount of problems that are happening.

SOME ONE HELP !!

[lambert]

All the dash is earthed  by two double black cables onto a m5 post on the engine side of the bulkhead above and right of the clutch master.

[westy 90]

ok thanks i will check that out and see what happens.

[westy 90]

checked the earth on the bulkhead and no problems there. Is this the earth for the head lights or are they earth somewhere else ? Also had a thought if it was the main earth on to the chassis when the connection was lost the battery warning light should come on surly. just trying to rural out things.