Fuel Guage inaccurate when Caravan connected (And cure)

[Rattles Lurker Find all posts View Profile Close Rattles]

Symptom: With the Fuel tank full and the Caravan connected and Fridge Running on 12V the fuel gauge only reads 9/10 full.
Problem: It appears when the Anderson Plug and the 7 Pin connector Wired the Earth (White) wire was connected to a Bolt on the L/H rear of the Chassis. It appears the connection between Motor and Chassis is only a thin wire (Somewhere ?) on inspection connection to Body can be seen however to the chassis ?? and appears to cause a drop of potential and the fuel gauge reads low.
Fix: I connected a 10mm Sq wire between the Battery and the Chassis picking a threaded hole on Chassis directly below the battery.
and later extended the wire to both Connectors as I also believe it is not wise to use Chassis as earth return.
This resolved the low reading Fuel Gauge hope this may help other folk with the same symptoms.

[sparksy Senior Member Find all posts View Profile Close sparksy]

Re: Fuel Guage inaccurate when Caravan connected (And cure)

Hi Rattles
I had a similar problem on my previous 90 series except the lack of a good earth return burnt out the earth for the fuel guages. The earth for the power outlet uses the same wire and whilst the power wire has a fuse the earth doesnt and its only a thin wire. Similar symptons with eratic operation, it melted all the plugs back to under the dash along with the wires next to it.
Fixed it the same way by running a new earth from battery to rear wiring. Suspect it was the trailer wiring for auxillary power.

Wayne