On my old CJ, a problem such as you describe would reqire changing the turn signal switch inside the top of the steering column. If fact, I have done it twice.

Unfortunately, I have no experience with XJ's, so I don't know how yours is set up.

Have you purchased an aftermarket repair manual for your model?

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.