Only Getting 6-7 Volts To Fuel Pump?

I only have 6-7 volts going to my fuel pump. I have replaced the fuel pump and the fuel filter and I have replace the relay that is the second relay back from the front of the passegers side of the engine. I believe this is the Fuel pump relay. I have an 87 XJ Laredo that is really getting on my nerves. Help Please I have no other ideas left besides the ballast resistor which I haven't found yet if it exists.
Thanks,
Zac

if there is only 7 volts at the pump than there is resistance. check the power at the relay. if there are 12 volts there you could have corrosion or a partial break in a wire.

The ballast resistor would drop the voltage -- that's what it's for. I don't know what it's supposed to reduce it to, I always assumed it was 9 volts but that was a guess on my part.

The early 87s didn't have the ballast resistor, but there was a TSB on installing it to reduce fuel pump noise. I have not seen the TSB so I don't know where it would have been installed. On the 88s it's on the inside of the driver's fender, adjacent to the airbox.

My 87xj was manufactured in the fall of 86 and the ballast resistor is on the fire wall above the master cylander and obviously not installed at the factory.

Check out the ballast resistor, mine was around 1 ohm or so. If that checks out, compare the voltage at the pump between the ignition in Start and the ignition in Run. Mine had a corroded wire splice in the big loom under the coolant bottle, where 5 red wires come together; start voltage was 13v, run voltage varied between 1.2 and 8.9 volts, depending on how wet the connection was. Undid the tape and lots of green stuff came out, not exactly the best conductor.