Truck Repair: 96 ford f150 fuel gauge, gasoline tanks, fuel gauge

Question
Hello,
My grandfather owns a 1996 ford f150 pickup truck. it has about 65,000km (not miles)on it,  and it has 2 gasoline tanks.  just recently the fuel gauge on his dash doesnt work. it just stays on empty the whole time.  It does this with both gas tanks.  all the other gauges on his dash does work though.  any suggestion?  Thanks
-Jon

Answer
Hi Jon,
I would probably wiggle the connector on the back of the instrument cluster. May just be a poor connection.
Might even need to remove the gauge and reinstall it.

There is a connector on the tank selector valve that I would also unplug and reconnect, cause when it changes tanks, it also changes sender connections.

Van