Fuel Guage issue

I have a 1973 series III with a non functioning fuel guage. I have shorted the wire at the sending unit on the tank to ground and the guage does not deflect to full. So either a wiring issue or the guage itself. Next step to remove dash and look at connections on the stabilizer?

If the temp gauge works accurately prob gauge wiring , then check the wiring green black wire to earth or test with your own earth onto the gauge terminal

Welcome

Check youve got voltage at the sender first then check continunity at the sender then work back...

Thanks. There is voltage at the sender, but only about 2v. I will pull the panel and see if there is anything amiss.

ve6sh said:

Thanks. There is voltage at the sender, but only about 2v. I will pull the panel and see if there is anything amiss.

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Well I go the instrument panel loose, but in the process one of the retaining clips for the bolt end of the screw broke. Can anyone confirm the voltages I should be seeing out of the stabilizer? Is 2-3v typical at the sender end of the wiring? The heat guage works fine so that should rule out replacing the stabilizer?

Thank you

I believe the voltage output is 10 volts to gauges but is pulsed to keep it stable at 10 volt along the lines of the old flasher relays a bimetal strip heat up break the circuit cools down and makes the circuit you can get electronic units to replace this item .
you may have to set your DMM on AC voltage to get an accurate reading
as the temperature gauges is working this would rule out the voltage stabiliser as it feeds both gauges ,if you ground the fuel gauge output briefly and it read then the problem is the wiring or the fuel sender or it's connections .so if the gauge does read when output grounded then connect wire back on gauge and ground the wire at the fuel tank end if this causes the gauge to read the problem lies with the fuel sender connections or the sender is faulty.

Having taken a closer look at the temp guage I note it barely is registering. To me that suggests the stabilizer is shot. I have grounded the wire at the sending unit and it does not deflect the guage.

If you’re only getting 2v at VS then something wrong , see what voltage coming into stabiliser and that should be battery voltage if so and only 2 coming out deffo time for new one .
I replaced my fuse box recently as voltage was wavering around 6-12v which I discovered was loose riveting on the terminals

Thank you all for your help. Unfortunately a previous owner has wired in a lot of accessories (winch, tach, fog lamps, stereo (!) and a cigarette adapter) so I am having an issue tracing the wiring diagram.

I will try a new sensor.

when you are grounding do it by a temporary wire connected to the battery and check the earths on the instrument cluster as they will affect the stabiliser and gauges

Get one of those little red bottles. Fill it with fuel and keep it in the back.

It’s worked for years

Bobsticle said:

Get one of those little red bottles. Fill it with fuel and keep it in the back.

It’s worked for years

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Yes, that is an option!

Any tips for removing the speedo cable? I need to do that to replace the stabilizer. It has a plastic clip on the end that goes into the speedo. For the life of me I cannot remove it. Does it just twist of?

Thanks

From memory I think you squeeze it and it pops off the securing lugs , if you get phone camera behind you might see where to squeeze , if not moving squeeze 90degrees around, there may be a little lever on it that you press to release it

As steve2286w said

Thanks all for the replies. Got the speedo cable off (what a hassle to reconnect). Replaced the stabilizer and still no luck. But, shorting the sending wire at the sender did at least give the gauge some life. Went to about half scale instead of full. That suggests it is the sending unit although given the gauge did not fully deflect I suspect it may be the issue.

Tim