FUEL GAUGE WIRING

BARON · Post by **BARON** » Mon Jul 30, 2007 3:59 pm

Hi Guys ,
Please help me with the wiring of the fuel gauge on my buggy. ---beatle tank and only one wire to the gauge (not connected ) There are two terminals on the gauge one marked --G-- I think -G- is for ground but if I earth that where does the power come from if Iconnect the wire from the tank to the other terminal on the gauge. I can not get to the fuel sender unit to see whats going on there without taking the whole body off.
What is the correct wiring arrangement?
Baron.

Merlin · Post by **Merlin** » Mon Jul 30, 2007 4:06 pm

Beetle tanks are mechanical...unless the late ones changed, which I'm not aware of?

N.

Post by **fig** » Mon Jul 30, 2007 4:09 pm

I don't have a wiring diagram in front of me, but a fuel gauge is basically just an ammeter (reads strength of current). An ammeter should always be connected in series with a resistor. The sender in the tank is your resistor; in fact a variable resistor attached to a float, so the varying levels of fuel in the tank give differing current readings to the ammeter (gauge).

According to the wiring diagram the hot wire goes to the gauge, supplied from the + terminal on the flasher relay. The G terminal on the gauge connects to the sender, which is earthed.

Post by **fig** » Mon Jul 30, 2007 4:10 pm

Merlin wrote:

Beetle tanks are mechanical...unless the late ones changed, which I'm not aware of?

N.

The Beetle fuel gauge changed to electric when the gauge was merged with the speedo for the 68 model year.

Merlin · Post by **Merlin** » Mon Jul 30, 2007 4:21 pm

Aaaah, OK.

Learn something new everyday.

N.

Post by **fig** » Mon Jul 30, 2007 6:54 pm

fig wrote:I don't have a wiring diagram in front of me, but a fuel gauge is basically just an ammeter (reads strength of current). An ammeter should always be connected in series with a resistor. The sender in the tank is your resistor; in fact a variable resistor attached to a float, so the varying levels of fuel in the tank give differing current readings to the ammeter (gauge).

IIRC, you should have a power wire to the sender, a connection from the sender to the gauge, and the gauge should be earthed.

I will double check this evening when I can consult a factory wiring diagram.

OK, so I was talking BS. According to the wiring diagram the hot wire goes to the gauge, supplied from the + terminal on the flasher relay. The G terminal on the gauge connects to the sender, which is earthed.

BARON · Post by **BARON** » Tue Jul 31, 2007 11:58 am

Thanks Fig,
That make sense, I looked at two type 3s last night and they look the same. The white wire on the first picture is just a home made earth to the body [img][img]http://img215.imageshack.us/img215/370/s5000688eg1.jpg[/img]
By MAN5011, shot with <Digimax> at 2007-07-31[/img]

[img][img]http://img74.imageshack.us/img74/9180/s5000689yo1.jpg[/img]
By MAN5011, shot with <Digimax> at 2007-07-31[/img]

Baron

Blitzkrieg · Post by **Blitzkrieg** » Tue Jul 31, 2007 12:58 pm

Are these Type3s available for spares?

Post by **IMPI** » Tue Jul 31, 2007 8:18 pm

on a beetle dont forget that the wiring needs a vibrator in the line in order to protect the fragile gauge (it is the relay like item on the back of the gauge.