Two fuel level sensors - one fuel gauge

**Mulgo** · 8th September 2008, 11:50 PM

I want to connect the fuel level sensors of the main tank and the aux tank via a on/off switch with the fuel gauge.

- Cable from main tank to switch connector [1a].
- Cable from aux tank to switch connector [2b].
- 1 cable from switch connector [1] to gauge.
- 1 cable from switch connector [2] to gauge.

A little LED light should indicate when I have the switch on aux tank - to prevent confusion. I have the LED installed just next to the fuel gauge on the actual dash.

I thought by connecting the LED to [2] at the switch would do the trick - but no.

Any help would be very much appreciated.

Cheers,
Daniel

**p38arover** · 9th September 2008, 12:40 AM

I've just had a look at the Defender wiring diagram for the fuel gauge and I'm sorry to say that probably won't work.

Without a sketch of what you are doing, I am making some assumptions. It seems, from your description, that you are effectively wiring the LED in parallel with the tank sender. The LED might light dimly when you have a full tank of fuel but it won't when the tank is empty.

The wiring of the fuel gauge circuit is:

+12v (Ign) ----> gauge ----> tank sender ----> earth.

I think you need a DPDT switch. One pole is used to switch the senders, the other pole is used to switch power to the LED.

**Blknight.aus** · 9th September 2008, 05:03 AM

I'm backing Ron.

double pole double throw switch one set of contacts switches the gauge wiring the other set the indicator...

if you got really tricky and got a 3 leg dual colour LED you could set it up so that the indicator didnt turn one light on and another off but just changed the led colour....

**p38arover** · 9th September 2008, 06:56 AM

If you like I can sketch something up and post it here (I couldn't do that from my location last night)

**Mulgo** · 9th September 2008, 09:35 AM

Hello Ron,

Will try to get one of these switches today - assuming Jaycar has them.

Is the below sketch correct?

Thanks, mate.

Daniel

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Two fuel level sensors - one fuel gauge

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