Welcome to TRS
What engine do you have in the 1988 Ranger?
Automatic or manual trans
2WD or 4x4
On the starter RELAY(on the inner fender), some call it a solenoid it isn't, lol.
There will be 2 larger posts, all the power wires are on 1 of the large posts, battery, alternator, fuse box ect............all on the one post
The other larger post will have ONE, and only ONE, wire, and it runs to the start motor, starter motor can not continue to run if this one wire does not have 12volts.
So why this wire continued to have 12volts is the question to be answered
Now starter relays come in 2 flavors, 3 post and 4 post
Two large posts and either 1 or 2 small posts
If two then they will be labelled "S" and "I"
The "S" post is used to activate the Relay, so it is connected to the ignition switch.
Ford has used a Red/blue stripe wire for the "S" post for 40 years, so Red/blue wire goes onto that post.
No other wires
"I" post is not used, it was used to power the coil when starting an engine prior to electronic spark systems.
Miswired starter relay could cause the problem
Or failing ignition switch
Remove Red/blue wire and reconnect battery, if starter doesn't start up again then good.
test for voltage on the Red/Blue wire should be no volts
Turn key on test volts again, no volts
Turn key to START, should see 12volts
Release key, should be no volts again
If Red/Blue wire has volts when it shouldn't then ignition switch under steering column is probably bad, but could be shorted wires if there is voltage all the time
Once you have solved the starter motor issue
Do a 50/50 test to see why engine is not starting
Remove the large air tube from the intake manifold
Open the throttle and spray some gasoline or Quick Start(ether) into the intake
Try to start engine
If engine fires up but dies, then fuel flow from injectors is the problem
If it doesn't fire up then Spark is the problem
50/50