Dakota VHX gauge and fuel level sensor

[Meddle]

I have dual fuel tanks on my 74. There are no electronic fuel pumps. The PO installed a Dakota VHX gauge but never wired a ground for the fuel sensor. I figured this may be why I am seeing erratic fuel level readings, specifically when the headlights are on.

To confirm this, I jumpered the “FUEL -“ terminal on the Dakota control box directly to the fuel sensor ground on my main tank, which the PO had attached to the chassis. Per Dakota, “FUEL -“ should not be grounded to chassis, only to the fuel sensor ground. With this change, the ohms readings are +/- 8 ohms with the headlights on/off, which is a vast improvement. I think I can live with this and I understand this is fairly normal operation.

However, this got me thinking, what is the proper way to ground the auxiliary tank as well? Can I simply splice the ground wire from “FUEL -“ so it branches to both main and aux tank sensor grounds or would this reintroduce the issue?

 

[Meddle]

Just to report back, I split the “FUEL -“ ground from the Dakota control box to each of the fuel sensor grounds on my main and aux tanks and the gauge appears to be measuring correctly for both tanks, toggling with the fuel selector switch on the dash. I am seeing only a 3 ohm bump with the headlights on versus off.

 

[ba123]

You really only need to put your fuel sender side to common ground and then your control box fuel sender ground to common ground.

At least that worked for me.

Then just the signal wire to the VHX box and input settings

 

[Wild horse 75]

I’ve successfully run many Dakota digital gauges without connecting the ground. That doesn’t mean you shouldn’t. That fuel- wire is to complete a fairly sensitive circuit. It should only be connected to the ground of the sender even if the sender has a chassis ground through the tank.