I found this table online and I apologize for forgetting where, I’d like to be able to credit the source. I think there have been posts on the Samba with the same info.
In any case, the VW is used in Bentley procedures to test fuel and temp gauges.
David B. commented:
The Vanagon gauges are electrically the same except for the blinker circuit in the temp gauge.
Gauge resistance ~52R, input voltage ten volts plus/minus a half for tolerance of +/- half a needle width.
Top mark ~35R (fuel full or temp ~130C)
Temp blinker starts ~45R (~125C)
100C touching high side of LED ~82R (OE sender)
90C touching low side of LED ~106R (OE sender)
Top of reserve ~170R (adopted in later models as the calibration low point instead of bottom of the gauge)
60C/empty/bottom mark on gauge ~265R