On a 1995 4.3LX is the fuel pump safety switch located near the oil pressure sending unit serving double duty to set off the audible sounder in a low pressure situation or is there another switch somewhere? Engine serial 0F588532
There are three switch/senders on your motor. The oil sender to show pressure on the gauge, the fuel pump switch to turn pump off if oil pressure is lost, and the warming horn switch that sounds the horn.
In the following link, Item number 12 is the switch for the oil horn while item 10 is the oil psi for fuel pump power and item 6 is for the oil gauge... https://www.perfprotech.com/mercury-...0?umodel=20955
Item 12 should be more to the port side behind the rear intake manifold sort of by the distributor assembly.