General 99 Ducato, earthing problem???

[Jocten]

Hi all, a newbie here.

I have a motorhome based on a 99 Ducato chassis with the 2.8 Tdi engine. Recently whilst driving, when I have switched on the headlights and cab fan heater, the temp gauge reading rises above the usual 75/80 degrees, and the more I switch on, the higher it goes, up to about 110 degrees.
Switching things off sees the gauge reading decrease again.
I cleaned and retightened the earth connections at the neg battery terminal, which appeared initially to have done the trick.

Whist on the driveway, I got the van engine nice and warm and whilst running at idle, I switched everything on. The amp meter went into discharge by about 10 amps, until the AC compressor kicked in, then it went to 20 amps. When the AC kicked out, it went back to 10 amps and never did return to charge. Meanwhile, Batt 1 (starter) read 11.5 volts and Batt 2 (leisure x 3) read 12.5 volts.
With everything off, I connected a good quality, heavy duty copper cored jump lead between the engine and the body, switched everything back on, and this time the amp meter showing a good charge, only went into discharge by about 3 amps when the AC kicked in, and returned to charge when the AC kicked out. The more I switched off, the more it went into charge. A definite earthing fault appears to be on the cards. :bang:

If this is the case, can someone please tell me where the earthing points are in the engine bay area, and where the earthing strap runs from, and where to?
BTW, is this a common fault?

Regards,

Jocten.

P.S. Sorry about the long post.

 

[weatherforcast]

on my '98 non turbo the engine earth strap was held with a 10mm bolt on the starter motor. the bolt reacted with the aluminium on the starter and the thread corroded and the bolt came loose.
i cleaned up the earth strap and used a starter motor fixing as the earth point.

 

[sparkyfixit]

On the Ducato's, Relay's and Boxer's I've worked on, the braided earth strap has been bolted on to the front top side of the gearbox. I think it attaches to the body directly above. They all seem to corrode under the bolt where it attaches to the gearbox. Must be that aluminium again........

 

[ken page]

jocten, dont bother too much with the origional, get a heavy piece of cable and make your own. attach to the chassis and engine at suitable points ken