PHXSYS wrote:

> I want to drive the OEM fuel gauge used on most common vehicles.

  As long as it is the "old-fashioned" resistive sender type, then...

> I was wondering if I could use PWM to drive the gauge to ground?

  Absolutely perfect!  Use a FET to drive the gauge.  Do use PWM so
that the FET dissipates virtually no power.  Do *not* condition the FET
drive other than with a 100 ohm resistor in series.  It will tend to
generate RFI which can be minimised using an inductor in series with the
output side of the FET with a diode returned to the 12V battery voltage.
Do not put any capacitors directly across the FET, you may place one on
the other side of the inductor.

  Sound Okay?

  Cheers,
        Paul B.