What year XJ? If it´s a pre 91, the 30 pin on the fuel pump relay has constant power from a fusible link hooked to the starter relay. The fuel pump relay is activated in the run possition at the ignition, you can feel it click with your finger when some one turns the key to run. Should have battery voltage (or close) at one end of the resistor and 9-10 volts on the other end.
The starter relay bypasses the the fuel pump relay and the resistor in the start position, to give the pump a little extra power at start up.
Always possible a corroded connector, is allowing voltage, but not enough amperage.
I turned my relay block over and looked at the bottom, pretty shocked by what I found.
if your gonna be doing much electrical troubleshooting, Alldata does a decent job of breaking the wiring and componenets down into bite sized pieces.
