One-speed hvac fan: dash switch or blower motor?

nissan

#1

My 1996 Maxima SE used to have a four speed fan for heat, vent, a/c, and defrost. Now it has only one: top speed. Everything else works, meaning it still sends out hot or cold air: just lots of it or none.



What’s the likely cause? Is there another potential culprit? I’m hoping it’s the fan switch (it’s cheaper than a blower motor) but either way, is it a big job? Does the dash need to be disassembled?


#2

Simpler and perhaps cheaper than a switch. Replace the resistor box, or blower resistors. This is a DIY job if you can find the thing. Ask the guy at the parts counter.


#3

There is a resistor in the circuit and it has failed. It’s probably in the airsteam of the fan and accessible from the side of the heater box. If you see a piece screwed into the box with wires going to it, that’s it.


#4

There are two things that can cause this problem. Either the blower motor resistor block is defective, or the high speed fan relay is defective.

Tester


#5

He has high speed!!!