Just use a test light or volt meter for inertia switch, the inertia switch is a pass thru for 12volts, one terminal is hooked to FP relay, the other terminal is hook to fuel pump.
So Ground test light or volt meter to cab ground, then test if one terminal gets 12volts for 2 seconds when key is turned on, then test the other terminal the same way.
If both terminals show 12volts for 2 seconds then inertia switch is OK.
Just as a heads up, the computer monitors the inertia switch power, so when key is on after that 2 seconds you will see 5 to 7 volts on both terminals(if switch is good), that's just computer's monitor voltage, but it has no AMPs so can't run the fuel pump
Why was filter clogged?
Pump is not quiet, leave radio off
, open door and turn key on and off several times and listen for the pump.
It will run for 2 seconds each time key is turned on, and no this will not hurt the pump or system to do this.
If filter got clogged from something in the tank then 3 days or so might be about right for it to clog up again.
I would pull it off again, then put a bucket down and turn the key on and off again and have a look at the fuel coming out.
When you changed the pump did you see the "sock", in tank filter, and was it clean, or did pump come with new filter?
Also just to take it off the table, pull off the gas cap, if you hear alot of air being sucked in when loosing cap then EVAP system and vent may be the problem.
The EVAP system sucks air out of the tank when engine is running, prevents gas fumes from polluting our air
If carried to the extreme then it could cause an air lock, so much suction in the tank that gas can't be pumped out after awhile.
EVAP is suppose to vent the tank before that happens.
You should usually hear some sucking noise when you open cap to fill up but just a little.
One more thing while we are at it
Non-Motorcraft fuel pumps don't have the best track record with Rangers, 3 days may be a new record but just because it is a "new" pump don't think it must still work because it is less than a week old, could even be wire pulled loose on the top of the tank