My 2000 QX 4 has auto air, naturally.The HVAC blower doesn't respond (turn on at all) although the fan indicator lights operate normally. I ran current directly to the blower and it operates fine and at full speed. The relays are fine as well as the fuses so current is getting to the blower normally and the problem appears to be in the ground circuit. There is continuity from the blower to the fan amp and from the fan amp to ground. These symptoms are a little different from what I've read as pointing to the fan amp. From what I know the blower runs full speed when the fan amp fails. Agian, my blower doesn't turn on at all. Could this also be the mysterious fan amp?

I woudl try buying a fan amplifier and see if that fixes it.. As long as your careful and just plug it in real quick i bet the nissan dealer would let you return it.

The dreaded fan amp, it was. I'm back and running. $150 + tax for the fan amp at the dealer.

I learned you can test the fan amp with an ohm meter. The resistence accross the ground circuit leads on the fan amp (about 5k ohm) should match that of the resistence accross the input lead and the lead to the dasbord control unit. My broken part had infinate ohms from the input to the control lead. No connectivity, no fan.

Thank you, oh great one, and all at the forum.

Q-Rod

I'm having the same problem I think? Did your blower kick in and out randomly for a while or just not work at all. Mine is VERY intermittent, but mostly off. Where is the Amp located on your car (I have a 2001 Pathfinder but I'll bet it's close).

What is the part #.

Thank in advance for any help.