1990 pickup, 4th Fuel Pump Replacement

Did you ask the dealer the same question?
Is it mechanical failure or electrical failure?
Did you request to inspect the failed part?
At $99 per hour labor charge in my area, I would expect answers and you have the right to know.
Most common problem would be a poor electrical connection. The dealer will replace the part as a preventative. Taking time to track down a bad ground or determining which terminal has a poor connection could take to much labor time. The terminal may becoming oxidixed from temperature & humidity conditions and needs to be cleaned, tightened an/or replaced, and SEALED from inclement weather conditions. Reference voltage is only 5v and computers speak digital codes based on hundredths [0.01] of a volt. Funny how that little molecule called oxygen, can work for you or against you.
My mama always said, "Ask, and you shall receive."
;-)
Good luck,
"Stew"