Fuel guage

[colddeadhands61]

Hey all,
'99 K1500 Suburban gas guage.
First the history. Guy I bought the truck from said he had a fuel pump put in. The gas guage worked prior. Didn't work after it left the shop. He never confronted them.
I changed the cluster out of curiosity. No difference.
I think the shop effed up the sender when putting in the pump. Maybe something stupid like a bad ground ?
Any thoughts ? Or should I change the pump with an AC.Delco ? Any help would be welcomed

 

[Mooseman]

I would look at the wiring. Maybe one broke at the connector, which is possible given the age. If that looks ok, try to short the two wires for the gauge and see if the gauge moves. If that checks out, next is the fuel pump module itself.