Relays chattering, poss bad earth 2008 tdci

[flamingpie]

Hi,

I'm really hoping somebody can help. I have trawled this forum and also Facebook but nobody seems to have any idea.

Glow plug warning came on and cut out on motorway. Got it restarted but kept cutting out. Got home. Next day, relays under bonnet chattering/clicking randomly. Occasionally able to get it to start when relay settles down and not clicking so much but cuts out when relays start flickering again at a faster rate.

2 relays chattering are curly wire one (Glow plug?) and one with a picture of an engine on the symbol on the cover on the box.

Changed battery, renewed earthing to battery negative terminal and rubbed down metal to chassis connection for good metal to metal contact. Still chattering/clicking.

Each time the clicking happens, I hear the high pitched tone from the EGR valve in sync with the randomness of the relay making and breaking (sounds like high pitched morse code). Swapped relays over, etc, still no good.

Had mobile auto electrician out and after 1.5 hrs, he gave up, saying it was a loose earth somewhere.

I found the engine management computer and disconnected it's chassis earth and the chattering immediately stopped.

I reconnected and it is now just randomly chattering, sometimes at a slick every few seconds, and other times rattling away!

I have followed the loom all around the vehicle and tightened all earths I can find.

Any ideas? I'd happily pay for any suggestion which finally fixes this fault!

Thank you in advance.