Just thought I'd update ya'll on the saga of the non functional gas gauge in my 92 240.
Gauge went dead earlier this week after a period of funkitudeness (high, low, drastic sweeps, etc).
1) Replaced the gauge with a known good one (easiest job). No Joy...
2) Checked power and continuity at sender/tank pump connector in trunk. Grey wire (sender) read 10.25 v with engine running, Yekkow/Red (tank pump) read 12 v with engine running 0 v with key in #2 pos.
3) Shorted to ground (momentary) the Grey wire at the trunk, gas gauge went full top reading so the gauge works as does the wiring.
4) Opened the cover plate hatch to the top of the tank and found the plastic sleeve holding the wiring that passes theu the top plate of the sender assembkly to be completely sheared off. The remains of 2 conductors can be seen amid the rust, sender and tank pump +12 v feeds. Well no wonder it ain't reading! No juice = No Joy!

The replacement sender assembly is $80 from Groton plus add a new lock ring and gasket and 1 hr labor for removal, swapping the tank pump assembly onto the new sender assembly.

Despite info to the contrary (Bentley/Haynes) the late model 240's will run just fine with a non operative Tank Pump, just don't let the level get too low-since the sender is out I fill up at 200 miles on the clock.