Hello!
First post here! Thanks so much for reading this. I just bought my wife this great little '98 VW Beetle. The gas guage has been giving erratic readings. Start it up and it will say 1/4 tank, Shut down and restart right away and it will say 3/4, Shut down and restart and it will say empty. And at times the gas guage needle will bounce around. I just had my mechanic install a new sending unit today. After installation it still behaves the same exact way. My mechanic said that on the schematic drawing he saw that there is some module that is also a part of the gas guage system. Where is that located? Could that be my problem? Anybody else had a gas guage behave this way? And a cure? THANK YOU!!!!!

 

Welcome to the forum.

If you have replaced the tank sender unit with a new one then it sounds like you have a faulty voltage stablizer in the instruments. I wouldn't have thought that a 1998 Beetle wouldn't have had a module to control the fuel gauge.

The fuel gauge is just a modified voltmeter and as the voltage in the vehicle will go up and down with various loads we need to maintain a constant 10v to the fuel gauge (and temperature gauge) else the fuel will go up and down depending on voltage.

Obviously the Beetle is air cooled so it doesn't have an engine temperature gauge but that also needs to be fed with the voltage stablizer. Check all connections first.