Recently bought the truck and it’s come with quite a few issues. I just noticed this wire that was tucked under the battery and I’m not sure where it’s supposed to plug in and I’m having trouble finding proper wire diagrams. It’s a singular white wire with a red stripe. Any help is appreciated

 

Welcome to the forum

What you need is the 1993 Ford Ranger EVTM(electrical vacuum troubleshooting manual)
Ford publishes a Shop Manual set for Every Model Every Year, so Ford shops can work on the new vehicles that year, in this case 1993 Rangers
The EVTM is a separate book but part of that Shop manual Set, but its often sold separately

These show every wire and its location for all sub-models(XL, XLT, 2WD, 4x4) with all trims and options

Here is one on ebay: https://www.ebay.com/itm/37471091764...IAAOSwAlZkaqx6
These are basically FREE to use because you can resell them for what you paid when you are done using them, same as the person on ebay is doing
Other non-Ford published wiring diagrams will be useless, just FYI, lol

In my 1994 4.0l diagrams I don't see a white/red wire for engine system

EDIT

The connector's shape reminded me of the Oil Level sensor plug in
Drivers side of oil pan, and uses a single white/PINK wire

Diagram here: https://www.justanswer.com/uploads/w...7_053654_3.JPG

It runs a yellow "check oil" light on the dash

 

Yes that seems to be right! Thanks a ton. I will definitely look into those manuals as well.