On the back of the alternator is a stud/nut terminal, largest wire or 2 wires are connected there, that's called the B+ terminal
In 1992 that wire(s) on B+ runs to Starter relay on inner fender, connected on the same post as Battery Positive cable, should be several other wires on that one post
The B+ wire to starter relay has a Fusible link at the starter relay end that can blow/melt
Alternator B+-------------(wire)-------------------------------(fusible link)-Starter relay post
Key OFF
You would test B+ terminal for Battery Voltage(test battery FIRST)
Use the alternators metal case as the Ground for volt meter
If B+ shows battery voltage, EXACTLY, then the wire/fusible link are OK
If voltage is lower, even a little, then move Volt meters ground to Battery Negative
If volts come up to Battery Voltage then you have a bad Negative battery connection
With engine running
Just test voltage at the battery, should be no higher than 14.8volts, and no lower than 13.5volts
If higher replace alternator
If lower test other 3 wires on alternator
Starter relay
It will have two larger posts
One will be connected to Battery Positive by a larger cable, that post is the 12volt distribution point for ALL the vehicles 12volt power
So this post will have several wires on it, including the alternators B+ wire
The other larger post will have ONE CABLE, to starter motor, nothing else should be on that post
It will have 1 or 2 smaller posts
EACH will have a letter next to it, an "S" or an "I"
The "I" post is no longer used, since the early 1980's
The "S" post will have 1 wire connected, it comes from the ignition switch in the cab, it activates this relay which then activates the starter motor
Since the "I" post is no longer used a new starter relay may or may not have it, doesn't matter, as long as it has the "S" post it will work fine
And yes "S" does stand for START
"I" was for ignition/spark system, just FYI
And the larger posts are interchangeable, since "I" post is no longer used
So there is no Battery Positive post or Starter motor post
As long as ALL the other wiring is on with the Battery positive cable and the Starter Motor cable is on its own on the other larger post, all will work fine