help whereis it? how do i know if its good? how do i replace? thanks!

okay son, the reverse lights are controlled by the NSS, ( neutral safety switch) located on the side of the transmision, I assume your talking about an automatic trans. Its a very common problem on these jeeps. It is an expensive switch to buy, approx. $3-400. Most people remove it from the trans, take it apart and clean it out, this usually works. Here is a write up on the whole procedure, click on this link.
http://jeepin.com/features/nss/index.asp

I found this. Also explains how to clean your NSS

http://www.cherokee-jeep.com/1-2swremov.htm

I had the same problem, first Check Engine light came on, OBD II trouble code P0705 was displayed. I got quotation of this part. But I found this link. I cleaned up myself and I didn't pay a dime.



Hope to be usefull