1996 Ranger. Fuel gage goes from Empty to below E when you turn the ignition on, regardless of how much fuel I have. It never goes above E. Replaced the sender and bypassed the anti-slosh module. Truck runs fine. Checked fuses. Last week I raised the bed on blocks. Checked the sender, 77 ohms with 1/2 tank. I happened to look at the dash and it showed 1/2 tank on the gage for the first time in 4 years. I cleaned the connector and tugged at the wires to be sure it was ok. Put the bed back on and again the gage doesn't work.
I have inspected the wiring harness and connections. Removed the front seat and pulled out the bushing in the floor. Everything looks suprisingly clean. I assume it is shorting to ground. Anyoone have a suggestion on where I should be checking? How is the bed shorting the system? Please help. BB

 

I would start at the cluster, the yellow/white wire, pin 12 on 12pin connector, check is OHMs to ground, should be 77ohms if still 1/2 tank
If 0, or lower than 16 ohms, then yes, yellow/white wire is shorted to ground some where

You could run a new wire to sender

If yellow/white wire is 77ohms then problem is in the cluster

 

RonD,
Ignition on. 12 pin connector off instrument cluster. Yellow/white wire to ground is 0.000 ohm.
I will run another wire, probably this weekend. It still baffles me how it came on with the bed off. The harness is so clean.
Thanks for the help. BB

 

Hard to say why it did that, wires from the top of tank should go down to inside of drivers side frame rail, bed shouldn't touch them, look at the two front bolts that hold the bed down to frame, may be drivers side bolt is pushing on harness and yellow/white wire has a bare spot so is shorting to its ground wire or the bolt