probably the sending unit in the gas tank attached to the fuel pump module is not working. you will need to most likely order fuel pump w/ sending unit Answer: The float is made of brass and over time they leak and sink causing the fuel gauge to read empty. The '84-'85 Bll 2.8L did not have a fuel pump in the tank.
bad ground or float stuck 2 possibilities i can think of
On a 1992 Ford Bronco : The electric fuel pump is INSIDE the fuel tank
The float in the fuel tank may need to be replaced.
how do I replace a fuel pump on a 1993 Ford Bronco 302 5.0 L
The sender is in the fuel tank and requires you to drop the tank as that is the only way to get to the hose and wires.
If it is the same as the ( 1996 ) Ford Bronco : ( Relay # 2 is the fuel pump relay )
where is fuel shut off switch for Ford Bronco eddy Bauer
On a 1996 Ford Bronco : The ELECTRIC fuel pump is INSIDE the fuel tank * it is installed through an access hole in the top of the tank
The fuel pump is located in the tank
The fuel presure for the 2.9 liter V6 in a Ford RANGER is ( 30 to 40 PSI ) I assume your Ford Bronco II , 2.9 would be the same * with fuel injection
In the gas tank
A person can visit a Ford dealership and ask for a 1989 Ford Bronco fuel diagram. Many times the Ford dealers will have mechanics on hand and they can give a customer a copy.