Recently purchased a 1996 Ford F-150 for my daughter. Got it home and flipped tank selector switch to rear tank while engine was running. Truck immediately died, switched back to front tank truck started immediatley all functions normal. Removed cap to rear tank and fuel started coming out under pressure let drain for a bit and it eventually stopped but was full to the top of fill tube. Went back to selector switch and turned key to on position could hear front tank pump prime and then stop. Turned selector to rear tank repeated same thing but no sound from rear pump. Bad pump? Just looking for confirmation before I tear into this and replace the rear pump. Am I overlooking anything?

 

yup must prob replace selector switch.

 

So Lostinafog you think it is just the selector switch and not the pump?

 

The symptom of the full rear fuel tank is the classic fuel transfer problem on the trucks of this era. The root cause is not the fuel selector switch, it's 100% electric, it is a bad shuttle valve inside the rear Fuel Delivery Module.

Your second symptom of no apparent fuel pump operation on the rear tank could be a bad pump or indeed a bad fuel selector switch. Best bet is to measure the voltage at the rear pump.

To fix the fuel transfer problem you need to replace the rear Fuel Delivery Module. Some have tried replacing just the pump, but that has mixed results. One way or the other you probably need to drop the rear tank.

 

it is the most problematic as it carries full voltage through it, no relay. it`s a DP/DT switch one side is gauge the other is fuel pump.
fyi the way it is mounted to the dash bezel is real easy to break the mount post sooo B careful not to stress em more than absolutely necessary .
can test the center terminal is 12v power to pump can make a jumper & after you disconnect wiring plug jump terminal it will be the larger gauge wires think the ones to the right looking at the plug if key on pump runs then it`s your prob.