[C320-list] Fuel tank sending unit wiring

[Wandering Star via C320-list]

After several hours of gaining access to the top of the fuel tank in the starboard aft section of the boat, I discovered the wiring on the new sending unit does not match the wiring on the original unit.

The original unit has a pink wire, which I know snakes up to the instrument pod and the gauge. The new unit has a pink wire, which I assume I will splice to the old one with a butt connector.

In addition to the pink wire, the old unit has a spade connector with two wires coming out of it. The wire on the right literally lays on top of the fuel tank and is wire tied to the fuel fill hose all the way up to the underside of the deck and terminates on a bolt held down with a wing nut. There is no gauge there, there’s nothing up on top of the deck, it just terminates there.

The second wire coming out of the connector on the left loops forward to a metal tab that is molded on top of the tank and is attached with a ring connector. Also coming off of the tab is a black wire which snakes up to the instrument pod. I’m assuming that is the ground.

The new sending unit has a black wire which I’m assuming is the ground. What I do not know is which of the two wires coming out of the spade connector do I splice the new black ground to. The one on the right that goes up underneath the deck or the one on the left that goes to the metal tab.

I took pictures, but I can’t upload them here. Happy to send them via email if you’re so inclined to share your opinion.

Thanks!!

Sara
Wandering Star
#707/2000
Seattle

[Dennis Cookson via C320-list]

The intention here is to ensure that all metal parts of the tank and fuel filler are grounded, so the black wire coming from the instrument pod should connect to both the sender and the ground tab on the tank, and in turn to the deck filler via the wire already in place. So essentially you are connecting all these black wires together at the tank. And of course pink goes to pink.

Dennis Cookson
'Catalina' #577

> On 20 Apr 2025, at 03:32, Wandering Star via C320-list <c320...@lists.catalina320.com> wrote:
>
> After several hours of gaining access to the top of the fuel tank in the starboard aft section of the boat, I discovered the wiring on the new sending unit does not match the wiring on the original unit.

[SARA SCHROEDER via C320-list]

Thank you!!! I figured that's what it was but given electricity is a stretch for me I started questioning myself. Really appreciate the reply and simple explanation. Headed back down to turn my body into a pretzel in the stern :>

With gratitude,
Sara