I got a 99 Ford Ranger pickup truck motor transmission will it go in my 2001 Ford Ranger got a 3.0 in it are the wiring harness the same

 

If the 1999 is a 3.0l engine they will be similar but not the same, some re-pinning of connector will be needed, just use the 2001 wiring harness and swap upper intakes
If 1999 is not a 3.0l then it will be very different, and would use a different computer as well

If both are manual transmissions then reverse lights are the only wiring, but connector may be different, just swap out the switch
If automatic trans then wiring connector will be different, 1999 3.0l used 4R44E trans, 2001 3.0l used 5R44E trans
If not 3.0l then along with 1999 computer and engine wiring harness, get its transmission wiring harness as well