I have a 1989 Cherokee 4.0 and the reverse lights won't turn on when I put it into reverse, but randomly will every so often. Pls help

 

One of the first signs of the NSS(neutral safety switch)needing serviced.

 

I don't know if it's the same on all years, but the reverse switch is part of the NSS. Check this out, might just need a cleaning.
http://www.go.jeep-xj.info/HowtoNSSrebuild.htm

Edit: looks like Earl beat me to it, so I concur with him.

 

Jeez. All that for just reverse lights. Same issue with my dads '95 Grand Cherokee. Is it the same with that model too?

 

hi,i have had my xj for 16months now and there was a problem with the NSS,soon after i got the xj i removed the NSS for cleaning etc,once that job was done i put it back on,maybe by luck i put it back on in the right place for P and N starting and also for the reverse lights to work when in reverse.
now only a few days ago my reverse lights stopped working when i selected reverse,so i got under the xj and with a 12mm socket i set about undoing the 12mm locking bolt for the NSS,and with the aid of a helper to watch the reverse lights i readjusted the NSS..with the ignition on and the auto selector in R.now the reverse light work every time when i select R.
maybe thats all you need to do,if the NSS has not been removed for cleaning may i suggest that you remove the switch and clean it out and then put it back on and adjust it for P-N and R...;-)

 

As I said that's usually the first sign. Next for me was not wanting to start in PARK then intermittently in NEUTRAL. I didn't find out until after I serviced it that it was also affecting how it shifted in 1-2.