Last week I replaced the starter since I thought it was internally shorted. Today the same symptoms occurred. I parked the truck, turned the key off and the engine continued to crank. The positive battery terminal has a bolt and wing nut to secure the 2 "hot" leads. I removed the starter lead and the starter stopped turning..

Previously I tried removing the starter relay, but that had no effect of the symptom.

Question 1: If the starter relay is pulled, can a faulty ignition switch still call for the starter motor to engage?

I'm looking at wiring diagrams. I'm good with electric once I get past being overwhelmed.

 

Has anyone got a nice wiring diagram for a 98 XJ Sport 4.0? My manual is at my sons house. All the internet drawings are kind of small.
Links or files?

 

Try your local library for a Chilton's or Haynes or a database.

 

There's another wire connected to the solenoid besides B+. Disconnect that and see if starter runs when connected to battery. If is does solenoid is grounded and it's back to parts store for another starter (but doubt that cause that would probably make things pretty smoky).

If starter remains off then jump that connector on the solenoid to Terminal 87 on the Starter Relay. If things return to normal then that wire is grounded somewhere. Take harness apart to find it (there's only about 2 feet of harness, and anyway the problem is probably down near the oil filter).

 

The solenoid contacts could be welded closed. I just replaced the solenoid on my 98 XJ because the contacts were worn out and the starter would not energize.

 

Well there it is. Sunday was beautiful in the NYC area so I was determined to trace this out and repair it.
I removed the nuts from the B+ and the relay control, unbolted the harness stay just upstream, and pulled the wire topside to work.
That one little strand. There it is. From the heavy B+ cable. I trimmed it off. I slit some heat shrink and enclosed both wires, taped nicely, (after a through bath in electrical spray), and reinstalled everything. Operating as designed.

I don't understand why or how the insulation was pulled back, or trimmed so much. I'm the second owner (265k). But it's a good repair that will last.

Thank you for the replies and suggestions.

Dez
NYC