The picture shows the common ground point for the battery , computer, & extra 3G alternator ground wire as described above in paragraph 2. A screwdriver points to the bolt that is the common ground point.
The battery common ground is a 10 gauge pigtail with the computer ground attached to it. Picture courtesy timewarped1972
Correct negative battery ground cable.
3.) The computer's main power ground (the one that comes from the battery ground wire) uses pins 40 & 60 for all the things it controls internally: it comes off the ground pigtail on the battery ground wire. Due to its proximity to the battery, it may become corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness.
All the grounds listed in items 1,2 & 3 need to bolt to clean, shiny bare metal. A wire brush or some fine sandpaper is the best thing to use to clean the ground connections.
Thanks for the reply but that's not it.
I remember those ground wires and I'm ok with them but the 2 - 16/18 Gauge Blk/Wht 2 in to 1 looks like they use to be in a connector but I can't find which one it was.
I'll try to find a 1993 5.0L LX wiring diagram to see what colors run on the left side frame rail.