Fuel Gauge (again)...need instructions on checking ohms

[Jeepwm69]

I did a search here, and from other posts it looks like my gauge might be bad.
Gas Gauge didn't work for years (read way over full). I dropped the tank, found the pink wire was severed. I spliced it back together, and everything's worked fine for a few months. The other day I looked down and it was just a hair under full (which was correct). Looked down a few min later and it was on 1/4 tank. Looks like 1/4 tank is where it goes for a bad ground on the tank or a bad gauge. Given that I have to drop the tank or remove the bed to mess with the sending unit wires, I'd like to check and see if I'm getting the proper signals at the guage first.
To check and see if the wires are sending the proper signal, I take my trusty voltmeter, put it on ???? setting, and then put the black post on the black connection on the gauge, and the red post on the pink post on the gauge, and then given that I have just a hair under full on the tank, I should read somewhere close to 90 ohms, correct? Do all this with the key off?

I really, really hope I don't have to drop the tank again. That was a major pain.