Recently my '02 X has developed a problem with the fan that blows the heat/AC/defrster. It only blows on the highest setting of "4". Anyone have any ideas on what the issue is and how do I fix it? I'm assuming its a switch or a fan somewhere, but that's just a guess. Any info is greatly appreciated.

Sounds like your blower motor has gone shorted out on all settings except the highest.... I dunno how handy you are for DIY... Sometimes they're tricky to get to, but you can buy the part fairly inexpensive.

I just replaced the chip for the blower and it took care of this issue. The part will have to be bought over the internet (Mexico) or from a Nissan dealer and shoud be around 40-45 dollars. Takes about 10 min. to replace.

I'm having the same problem and need some advise on how to replace the chip for the blower? Any idea will be greatly appreciated.

I don't have time right now but search the Xterra forums for "blower motor resistor". It's reasonably cheap and easy to replace.

I would also say the blower resistor. Also known as the variable blower control.

yes i remember a detailed thread on this subject..... use the search and you will find....lol

Purchased blower motor resistor for $37.00 at autozone.
Located under glove box.