63 fuel gauge (cont'd)

[Steve D.]

Reassembly in progerss, new sender, new harness, clean & tight grounds.

The fuel gauge deflects completly each way with 12V on one pin and the other pin grounded. The measured voltage at the input wire (light green) at the sender is 12+ V. With the green and brown wires connected to the sender terminals (ground wire also)I had no activity on the gauge. I lifted and lowered the float in the tank; still no response at the gauge. I disconnected the brown wire at the sender, and connected a voltmeter between the brown wire terminal and ground. Tank level is pretty low, maybe 1/8 full, and the meter initially read 12.42V. I raised the float to the top and voltage reading moved to 11.98V. I don't know what the specs for the sender are, but I expected a bigger voltage difference for full travel of the float arm. I guess the new sender could be bad out of the box, but I don't want to draw a hasty conclusion. Any ideas?

Steve

[Gerard F.]

Re: 63 fuel gauge (cont'd)

Steve,

Try this:

1. Disconnect the three leads at the sender.

2. Between the ungrounded terminals (brown and green) connect your voltmeter in the Ohms setting (adjust the meter for 0 ohms at full contact).

3. Moving the float up and down, the meter should read 0 to 90 ohms (or there abouts). If you don't get this flucuation (and I forget which way it is) with the float in the up or down position, then it's the sender unit.

If you get the flucuation, then clean off all terminals and reconnect connectors (green to the I, brown to the S.) If the gauge doesn't work and you are getting 12v between the green and black at the sender, then I would suspect an open or break in the brown wire to the gauge.

If you connect the green and brown together, while off the sender terminals, the gauge should go to full. However, if you reverse the green and brown at the sender, or put 12v to ground on the S terminal you could fry the resistor in the sender.

Try the ohms test first.

Jerry Fuccillo
#42179