It has been suggested to me that I replace the "B+ latch relay" on my cherokee to fix a starting issue. The problem is: I dont know what or where this object is? Any info? Anybody?

I did some searches for you here on AF and this is what I came up with:

(Please note my tip on using searches....)....

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"also know on later models as the auto shut down relay"

See Fig. 26:

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/15/3e/8f/0900823d80153e8f.jsp

http://www.dua1.com/AdminFiles/Jeep/88/relay_location1.jpg

"if the crank or cam sensor acts up, and the computer doesn't recieve a spark signal, the auto shut down relay or b+ latch relay will not let power go to the fuel pump, however, the pump will still come on for two seconds when you turn the key even if the crank sensor is toast depending on the year."

My explanation:

It is there for safety reasons....so the fuel system and ignition system shuts off in case of a crash.