Questions looking for help

[decade22ten]

I have a 1987 chevy fuel injected truck that will not start. it has dual tanks. the previous owner told me the passanger tank didn't work, now the driver tank is not working im quessing it is the fuel pump. would the diverter switch in the cab keep the passenger tank from working? i'm quessing that it is the fuel pumps in each. im going to buy a new diverter swith to eliminate it. i would appreciate any help on diagnosing the problem. just checking if anyone else may have had this problem. thanks.