Itinerant Air-Cooled

This is a weird one... I had a dead fuel gauge. Ran diagnostics while Colin was here in June, which determined it to be the gauge itself. Since then I have been running without and just writing down mileage. Which gets old after a while.

So I purchased a good used gauge online. Tested it with vibrator, sender, and 12V connected on the bench, as described here:
http://www.midsouthvw.com/TechTips/tech ... lGauge.htm
It worked! Needle moved as it should when float arm was moved. Then I tested the old fuel gauge. It did not move, confirming that it was indeed toast.

Installed the new gauge etc., into the cluster and in the bus and now nothing. I cannot get the gauge to respond under any condition, even when I jump the fuel gauge Brown/black wire to ground, which I think should get me something - regardless of the rest of the wiring?

Fuse is good. I have double-checked my connections on cluster and they're good. The sensor is plugged in back nice and tight with gasket and the float is free to move up and down, not binding. Brown wire with black runs to insulated tab, the straight brown wire to ground tab. Any ideas where to look next?

Squeebles wrote: Installed the new gauge etc., into the cluster and in the bus and now nothing. I cannot get the gauge to respond under any condition, even when I jump the fuel gauge Brown/black wire to ground, which I think should get me something - regardless of the rest of the wiring?

If you grounded the brown black wire gauge spade terminal with a jumper to ground and did not get needle movement, it suggests that the gauge is now toast. The gauge can burn out if the vibrator leads are inadvertently reversed . . .
Check for 12 volts to black wire at vibrator with a test lamp probe, the red one goes to the gauge itself.
Colin

Have power at the black vibrator wire. Now confused about how the gauge could be blown once I installed it, ,which I believe is correct ... pic of my setup below. Perhaps a faulty ground from the fuel tank sensor?

Squeebles wrote:Have power at the black vibrator wire. Now confused about how the gauge could be blown once I installed it, ,which I believe is correct ... pic of my setup below. Perhaps a faulty ground from the fuel tank sensor?

You would get needle movement if the brown/black wire were grounded at gauge, thus pointing to the sender ground path as your problem. Recheck for needle movement if you ground the brown/black terminal of the ground.

You need to check the output of the "vibrator" (voltage regulator) to the gauge. You cannot have 12 volts go into the gauge, it will burn up. See if you have around four volts, maybe five or six coming out of the red wire to the gauge.
Colin

Amskeptic wrote:

Squeebles wrote:
You need to check the output of the "vibrator" (voltage regulator) to the gauge. You cannot have 12 volts go into the gauge, it will burn up. See if you have around four volts, maybe five or six coming out of the red wire to the gauge.
Colin

12 volts coming out of the voltage regulator. So this then blew the gauge. What a drag, I now need new components of both. I am guessing that since all worked fine when placed on the bench I must have a fault in vehicle wiring which causes the voltage regulators to be burnt up.

Squeebles wrote:

Amskeptic wrote:

Squeebles wrote:
You need to check the output of the "vibrator" (voltage regulator) to the gauge. You cannot have 12 volts go into the gauge, it will burn up. See if you have around four volts, maybe five or six coming out of the red wire to the gauge.
Colin

12 volts coming out of the voltage regulator. So this then blew the gauge. What a drag, I now need new components of both. I am guessing that since all worked fine when placed on the bench I must have a fault in vehicle wiring which causes the voltage regulators to be burnt up.

You are late model gauge, introduced in early '74. Vibrator (voltage stabilizer) must match your late gauge. Sorry and good luck.
Colin

Thanks for the help Colin, got a new gauge and voltage regulator and works fine now.

Squeebles wrote:Thanks for the help Colin, got a new gauge and voltage regulator and works fine now.

Right on!
ColinDrowningInOdessaTXThunderstorm