Blower Motor Resistor?

[Guest TheBest42]

I have a 92 Pathfinder SE and my fan is now only working on the highest setting. I looked at the wiring diagram in the Chiltons book and I think it is the blower motor resistor that must be broken. The book doesn't have any kind of description or diagram about where it is though. Can anyone help? Pictures would be great. Thanks.

 

-Ted

[mws]

If it is the same as my '87, it is mounted into the ventilation plenum. This is the large black box behind the glove box that contains the heater core and A/C core. The bottom of this plenum actually hangs down a couple inches below the glove compartment and you can see it when driving. To get to the blower resistor module, remove the glove compartment and then the vertical metal plate behind it (4 bolts and 2 screws on mine). You will see a largish white 6 terminal connector plugging into a squarish metal cup doohickey recessed into the upper right front corner of the plastic box. That's it! It's up high enough that you must remove the glove compartment and metal plate.

Remove the connector, take out the inner two screws securing the resistor module inside the cup and remove the resistor module. About 3 minutes work once you figure out how to get those $*^#$ hinge pins out to remove the glove compartment.

 

The resistors (3 of them) will have values of only about .6 to 1.2 ohms each. They are large wire wound resistors, about 1/2" long and 3/16" diameter. They have a single bead of ceramic material applied to one side to dampen vibration, but they are not fully encased. Most of the resistor wire is exposed. And one will be glowing red hot during operation at speed level 3. These resistors are passing up to 30 amps! They get realllllly hot, which is why they are mounted where they are - the fan cools them as it uses them. Kinda neat idea, actually.

 

There is also a soldered thermal overload safety contact buried down inside the module between the resistors. That's what failed in mine - and my suggestion of the first thing to check in yours. If the resistor pack gets too hot, the solder melts and the contact opens up - and then the only switch settings that work are off and hurricane force. Sound familiar?

 

For my '87, the part number was 27150-06J01, and it cost me $14.96 plus a couple dollars shipping through North Texas Nissan. It was a special order. I'd be surprised if it changed between '87 and '92, but I don't know. Check with your local dealer or call NTN to see if the PN is the same. A Standard Motor Products RU-207 is also supposed to be a generic replacement, but I couldn't find anyone who could get one... they appear to be discontinued. Fortunately, the Nissan part was about the same price from NTN! My local dealer was more than double.

 

Root cause for mine failing: The previous owner lived up in the pines, and over the years enough pine needles entered the ventilation system until the plenum box was full enough that the needles were touching the resistors. One day, she turned on the fan and after a few minutes, the vents started doing their best fog machine impression. The local firefighters said it is a very common problem - and not limited to Pathfinders or Nissans. So vaccuum out the plenum box while you have the resistor pack out.

Edited March 17, 2005 by mws

[Guest TheBest42]

Sorry it took me so long, but I finally got off work early and had the energy to go look for it. I wish I had done it sooner because it really did only take me 3 minutes to undo the bolts and find the resistor. It was staring me right in the face once I took that metal plate off. Couldn't miss it. It was so easy to find and get too that I'm going to go to this junk yard that I know has a Pathfinder in it. Shouldn't cost more the $5-10. Thanks for your help and A+ on your explanation.