C4 fuel gauge malfunction
 

I have been looking all over the forums and cannot find anything about malfunctioning fuel gauges or how to remove the fuel pump on a 1997 Audi a6 Quattro avant. Has anyone replaced this/diagnosed this. My sons car is giving false fuel readings, goes up to mid fill level, and then quickly to empty. Car runs excellent other than this. Think it is the sending unit, relay or gauge itself. I cannot find out how to access the fuel pump on any forum or web link. Need help!