2004 Nissan Altima Blower Resistor

If you mean the blower only works on high, it could be the resistor that cuts down the power for the other speeds.

The blower motor resister is shot, It needs to be replaced,

automatic or manual a/c.

I'm going to assume manual but Auto is simular and i can give some direction if you have that as well.

There will be a black with tan wire at the blower resistor. This is the wire the HVAC control head grounds to turn the fan on high speed. With a test light hooked to power unplug the resistor, set the blower speed to high, turn the key to the run position. the test light should turn on when you probe the connector. If it doesn't pull the control head and back probe that same wire at the back of the control head with everything still plugged in. If the test light again does not illuminate the the control head is bad and not providing ground

If the test light does turn on when you probe the blower resistor connector plug the resistor back in. Turn the blower speed to the low setting. With your test light hooked to ground see if there is power on the black with tan wire. if there is turn the HVAC off and ground that wire with a jumper wire. the fan should run at high speed. If it doesn't you have a defective resistor.

THERE IS A BLOWER SPEED RESISTOR THAT CONTROLL BLOWER SPEED CHECK THAT

The heater blower is normally controlled by voltage sent to the blower via a resistor network.
In this case it seems that this unit also called the fan resistor is defective.
I assume that 4 is the position where the blower is running HIGH and in this position the blower is powered directly without using resistor for lowering the speed of the blower. In step 1 - 3 the blower is powered via the mentioned resistor network.

In my opinion the resistor network is defective.
Replace it !!!!.

The blower motor functions so most likely the blower motor resistor which is what produces the different speeds is burnt out.

The blower motor resistor is usually only switched into the circuit for the lower speeds and for the fastest speed the resistor is bypassed so I guess the motor needs to be replaced if it does not work in any position. However, sometimes the blower motor is not protected by a fuse but by an automatically resetting sealed circuit breaker usually located not far from the motor. The circuit breakers dont fail very often, If the fan works for a few seconds and then stops and then does the same thing several minutes later then the fan motor definitely needs replacing.

It needs to have the blower motor resistor card replaced.
It still works on high speed because on the high setting the voltage does not go through the resistor.
The resistor is mounted beside the blower motor and is easy to replace.
There you are, thank you for using FixYa.

KL

Two possible areas I would check using an ohm meter. First is the blower resistor which is usually located by the blower motor and looks like a cement rectangle or a ceramic tube with wires attached to it. The resistor should have very low resistance but should not read open from the common lead to the other terminals. If it tests good test the continuity of the fan switch. Some cars have a fuse for the high and low blower speeds so you can check your fuse diagram and look for two blower or fan fuses. Good Luck.

Change blower resistor.