fuel gauge

[4X4orNoX4]

hey guys, got a question about my fuel gauge in my 67 c20. im working on putting a cluster together a new cluster with some modern gauges in it. want to put a new fuel gauge in it but im not sure how they work. im looking at one that is listed "Empty/Full, 240 Ohms/33 Ohms". wondering what this means, how it works? plus how do I make something like this work in my truck? any advice, many thanks.

[ray_mcavoy]

Originally Posted by 4X4orNoX4

im looking at one that is listed "Empty/Full, 240 Ohms/33 Ohms". wondering what this means, how it works?

That means the gauge is designed to work with a sending unit that has 240 Ohms resistance when the tank is empty and 33 Ohms when the tank is full.

plus how do I make something like this work in my truck? any advice, many thanks.

The stock sending unit in these trucks is 0 Ohms when the tank is empty and 90 Ohms when the tank is full so it won't work with that gauge. You'll have to change the sending unit to a 240/33 Ohm unit that matches the new gauge. Exactly what you need to do that all depends on the tank you're using.

Or see if the manufacturer of the gauge you're looking at also offers the same style in a 0-90 Ohm version that will work with your stock sending unit.

[4X4orNoX4]

thanks for the info. did some looking around and found another gauge that's looks about the same and is listed 0ohm empty and 90ohm full. so this will work with my factory tank and sending unit? is it just a simple 2 wire hook up?

[ray_mcavoy]

Originally Posted by 4X4orNoX4

... found another gauge that's looks about the same and is listed 0ohm empty and 90ohm full. so this will work with my factory tank and sending unit?

Yes, that gauge should work with your factory tank & sending unit.

is it just a simple 2 wire hook up?

It should be a 3-wire hook up. One wire to +12V switched by the ignition. One wire to ground. And one wire to the sending unit. The sending unit is grounded to the tank.

The factory gauge has 3 terminals that are hooked up the same way. The rear tin on the factory gauge cluster serves as the ground so there are only 2 traces on the printed circuit for the fuel gauge.

[ole dollor]

I also agree with the above post....x2

[4X4orNoX4]

thanks for the pointers guys. hope to get it in this weekend.