Odd Earth Fault! Help!

[doilum]

Ok so driving along and car died. No power, no lights, nothing. Pushed to side of road and all of a sudden came back to life! Fine for a few days then last nights hen I came out of the gym went to start it and it was switching on but just clicking when I went to start it. After a couple of goes the clicking was less and the clock zero'd so I assumed battery, left it where it was and went home.

Bought a battery today, fitted it and still clicking, not turning over at all. I presumed then a fault with the earth but I didn't have the kit to test it so I called the AA. AA dude came out, car started off the jump leads with the earth to the engine block so you could assume then that the earth between engine and chassis was dud. Checked that and the Renault braided one was fine and there was an AA style one on it too, same place. Cleaned and refitted, no joy still but it would still jump if you earthed to the engine. AA guy took the second earth from the gearbox earth (the extra one) and fitted between the battery and engine and now all is fine!!!!!

Why on earth would the earth between gearbox and chassis play up like that as the are obviously not broken as the same cable worked when placed elsewhere? Scratching my head here! I'm more interested than anything as its obviously working fine now!!!!

 

[MicKPM]

Every circuit needs power and earth. If one earth is poor then the circuit won't work.

What makes you think the gearbox to body is the faulty earth, have you tested it? There's three earths under the bonnet for the EM/starting circuits so it could be either of them.

 

[doilum]

The AA guy tested that earth and that was the one at fault, even though the earth wire worked when relocated.

 

[The Chubby Pirate]

I had the exact same symptoms you had mate, wouldnt start, lights staying on, temp needle all over the shop etc

Swapped the earth strap from gearbox to chassis and its been fine since.