I'm not great with the electrical side of things so I'm asking for help in checking my work.. I'm trying to solve a fuel gauge problem (68, console) .

Problem--fuel gauge sits at full plus.

steps I've taken:

1. disconnected the line from the sender in the trunk and found:

a. when the line to the gauge is grounded the gauge reads empty--conclusion: guage and line to gauge are ok.
b. connecting an ohm meter to the sender line and find 20 K -- conclusion: sender ok since the tank is under half full and 45 K should be half.
c. make sure that the sender line and the gauge line are making a good connection--then connect them up--gauge sits at full plus.

Overall Conclusion: the ground to the sender is broken at some point?

Am I right to think this or have I missed anything? Is there any good way to deal with a broken ground without dropping the tank?

Many thanks in advance.

b. connecting an ohm meter to the sender line and find 20 K -- conclusion: sender ok since the tank is under half full and 45 K should be half.
c. make sure that the sender line and the gauge line are making a good connection--then connect them up--gauge sits at full plus.
Sender is NOT ok. GM sending units are 0-90 ohms. You are getting a reading of 20k, which is 20,000 ohms. The reason why it is still at full plus.

Overall Conclusion: the ground to the sender is broken at some point?

I would look at the ground wire first, where it connects to the frame. Make sure it is clean, tight and connected to bare metal. Use a star washer too, it digs into metal to make a better connection.

New or original gage? I had the same problem changed the gage and problem went away.

The gagues are original (but maybe not to the car). Some of the wiring suggests that the console was added later.

Thanks.