My son has a 2000 SE, with about 265k miles on it. Recently, his fan blower motor runs at MAX Speed only, and cannot be shut down. As soon as the key is turned to the Accessory Position, or starts the car, the fan blower motor starts, even if the Fan Control **** is in the OFF position.

We have changed the Blower Motor Resistor, but that did not help. The Service Manual Troubleshooting section calls for checking the ground circuit for the fan switch, but does not describe where that M58 Connector is located, so I have not been able to make that check.

I believe that the problem is with the Fan Speed Control Switch, but I have not seen any references that it can fail.

I would appreciate any help here.

 

My 200 SE has teh Manual Control system.....sliding ***** to set temperature settings.

 

The blower motor resistor (which is really a transistor) has shorted. You need to get a new one. When you are buying it make sure you specify manual controls because the auto controls use a different one that is not interchangeable.

 

Thanks for the quick response, Dennis. My son bought the new resistor, and installed it before he drove home. And he brought home the old one. I checked the resistance of both the old one and new one, and the resistance in each circuit was within factory limits. I even disconnected the resistor, and there was no difference in performance.

The Service Manual references a white connector, M58, but does not specify where it is located. I found a white connector on/near the blower, with 5 wires. The attached photo shows both the connector and where I pulled it from.. I thought it ight be the M58 connector, but the fan still ran even when this connector was disconnected. Does anyone know what this connector really is? I checked the continuity across each pin, and each connection had continuity, which does not make sense.

White Connector located on/near blower motor

 

That is not the connector for the blower motor resistor. That might be the connector for the fresh air/recirculate vent motor. The connector for the blower motor resistor is square and one of the wires is real thick as it has to handle 30 amps.

The blower motor resistor is not right by the fan motor. It is mounted in the main air duct roughly at knee height. I can't remember if you have to remove the glove box or not to get to it.

Click on the link below and go to page 148 and look at the drawing in the center of the page.
http://boredmder.com/FSMs/Nissan/Maxima/2000.5/HA.pdf

 

Dennis, you are correct. That connector I photographed is not the fan switch.
I had already bought and installed a new resistor. But that made no difference. So, on speculation, I purchased a fan switch from Nissan. Last weekend I pulled out the Center Console Module, which holds the audio and environmental modules. I then disconnected what I thought was the fan speed connector. When I did that, the fan stopped working. So I removed the environmental module, disassembled it to replace the fan switch, and put everything back together. The fan now works on all settings, including the "Off" position.

Thanks everyone! This forum is a fantastic resource!