ASAP HELP! no power is going to my blower motor in my 03 Maxima.
 

So I don't know how fast replys happen on this page but I'm at a loss, just got a 03 Maxima with a busted ac/heater. Originally thought the blower motor was messed up so replaced it with no success, the engine clicks on when I turn it on but no air blows out, fixed the resister and tested to find that there is no power going to the blower but I have power in my engine. I'm at a loss here and with the winter fast approaching I need my heater to work. Hope to receive some help soon thanks!!

There are 2 15 amp fuses located in the fuse box under the hood by the battery. Have you checked those? If you fixed the resistor, it is very possible those fuses blew.

Confusion - you said "the engine clicks on when I turn it on but no air blows out". What do you mean? Did you mean to say the a/c compressor?

And if there are further questions, please tell us if you have the auto climate controls or the manual controls.

I've checked all fuses and no issue there. And yes the compressor clicks on and power goes to my resister but there is no power going to my blower motor. I have auto climate controls.

You need to understand the flow of electricity for the blower motor.

12 volts starts at the battery, goes to the pair of 15 amp fuses, goes to the blower motor relay, goes to the blower motor. Once you have power at the blower motor, you have to get the power to ground. SO... from the blower motor, the power goes to the fan control amplifier (you call it the resistor), then through the fan control amplifier to ground. The fan control amplifier is the actual switch that makes the fan run.

The fan control amplifier is a transistor controlled by the HVAC controls in the dash. Besides the transistor, there is also a fuse in the fan control amplifier.

In your original post, you said that you "fixed the resister". What did you do to it?

If you want, here is a link to the troubleshooting section from the Nissan FSM. Start on page 94.

http://boredmder.com/FSMs/Nissan/Maxima/2003/HA.pdf

Personally, I think the fan control amplifier is bad

Okay I had a feeling the resisteris called something else. But we changed out the old one and put in a new one thinking that was the issue but still no power is going to the blower motor, could it be an electrical issue? I really hope it's not but I just need it fixed the snow has come and driving my car in the mornings is horrible.

The manual controls and the auto controls use a different fan control amplifier. With the manual controls, it is called a resistor and with the auto controls, it is called fan control amplifier. They look the same but they will not work in the wrong system. As long as you are certain that you got the correct part, then we can rule that out.

In the wires that plug into the fan control amplifier, there is a thick wire, blue with white stripe. This is from the blower motor. You should measure approx 12 volts with the ignition key is turned on. Unplug the wires from the fan control amplifier and jumper this wire to ground. The fan should run. If you do this, make sure you use a thick wire as the jumper. Also, you will get kind of a big spark because this will be about 25 amps.

If the blower motor runs, then plug the wires back into the fan control amplifier. Using your voltmeter, put the voltmeter positive probe on the blue/yellow stripe wire and the other probe to a good ground. With the ignition switch in the ON position, use the control panel to make the fan run. The voltmeter will give you a changing voltage for each fan speed.

Speed/volts
off --> 0.01 v
1. --> 2.6 v
2. --> 2.9 v
3. --> 3.2 v
4. --> 8.2 v

The voltage readings will vary from car to car, but will be about what I typed. The main thing is that the voltage reading changes from about zero to 8+ volts. If the voltage readings change and the fan does not run, then the fan control amplifier is bad. If the voltage readings don't change then the control panel is bad.

Dennis, i have no air movement in my car, i just checked the interior fuses 10amp, and then checked the "motor" relays (dual 15 amps) near the battery and swapped them with the "mirror heater" dual 15 amps relay from the passenger fuse box and still no air movement. do you think I should get the fan control amplifier at this point?

i replaced the blower motor itself probably 10 years ago with the common symptoms. but not this fan control amplifer.
all other threads on here people have some kind of heat or ac or air movement , I do not have any air movement no matter what settings ac , econ, heat, defrost etc etc. buttons work and it is ACC by the way not manual.

I cant thank you enough Dennis, it's insane how much you know and share with us.

i ordered the blower motor too, and will post updates

wanted to post an update it was a straight forward fix in my case and it was just the blower motor itself and not the fan control amplifier. thanks Dennis for your sharing your knowledge.

I have an issue where my blower wont blow on 4 and I just changed the resistor and that didn't fix it. I'm thinking I need new dash controls.

i think that may be blower motor too, IIRC that was my symptoms 10 years ago when i replaced the blower motor the first time. i would look around here further into classic blower motor symptoms and double check that isn't one.

You guys have some bad luck with symptoms. Bearings always went out in mine. The random screeching, though... O_O

and a good wack near the glove box when it stops to get it going again until a new motor come in

I intentionally hit bumps to do it :rolling_e