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Jay
Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 19644
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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Nissan altima: the blower stopped working (even on high)

Customer Question

I have an 02 nissan altima w/ 3.5 engine. the blower stopped working (even on high). The blower fuses are good. I have removed the resistor but don't know how to test. Is this the likely problem, or could it be something else.

Thanks,

Dave
Submitted: 6 years ago.
Category: Nissan
Expert:  Mike V. replied 6 years ago.
Chat Conversation Started
carguy1 :

Hi there! It is likely something else. The resistor is by passed when you put the blower switch on high. Do you have a test light?

Customer :

No but I have a meter

carguy1 :

Meter will work, one moment while I pull up the wiring diagram. I assume this is manual climate control?

Customer :

no, this is automatic

carguy1 :

Ok, there is no resistor in the auto a/c system. The part you removed, is it square?

Customer :

thought i read somewhere the resistor has an internal non resetable fuse. Is this a possibility?

carguy1 :

Full Size Image

carguy1 :

The resistor doesn't

Customer :

no

carguy1 :

It is just a flat card with resistors to slow the voltage so the fan will opersate at lower speeds

carguy1 :

Is it a flat 4 pin card type thing?

Customer :

it looks very much like the part you have highlited. # XXXXX part: 2W6003F 03

Customer :

there are 3 pins

carguy1 :

Ok, it's all good as long as we are talking about the same part so we can test it!

carguy1 :

lol

carguy1 :

Ok, I want to have you check for power on the wiring harness to the fan amp. Terminal 2 with the key on, check the blue/yellow wire for power to it and let me know. I will wqait

Customer :

the blue/yellow wire is much smaller guage than the other 2 wires and has 9v to ground

Customer :

the blue/white wire has 12volts to ground

Customer :

the black has 0v

carguy1 :

OK, so far so good. Plug the fan control amp back in and backprobe the blue/yellow for voltage and let me know

Customer :

same results

carguy1 :

ok, Next check the white/blue wire at the blower for power

Customer :

do i need to remove the glove box?

carguy1 :

Only if you can't see the wiring to the blower motor itself. It is a 2 wire connector, if you can get to it then no

Customer :

if i have the right one there is 12v at blue wire. the other wire is white

Customer :

white wire also has 12v

carguy1 :

Ok, one more test my friend, unplug the fan amp again and check for continuity between the white wire at the blower and the blue/white wire of the control amp harness

carguy1 :

that is normal until the fan is switched on

Customer :

continuity exists both with ignition on and off

Customer :

btw, all the tests you asked for, i did with ig "on"

carguy1 :

Ok, that's good. I lied though, I have a couple more tests to try. I would like to have you plug it all back in and see if the white wire goes to ground with the key on and the fan switch on. Sorry, I am not normally I liar but I want to get this right!

Customer :

no prob. are u asking if white has continuity to ground when system switched on?

carguy1 :

Yes

carguy1 :

the fan amp supplies the ground

carguy1 :

it has to lower the voltage, but the blower has a constant 12 volts

Customer :

white goes to ground

carguy1 :

Well, I suspect the blower is shot at this point. You can verify by removing it and then putting battery voltage and ground to it. If it doesn't blow, then it isn't going to move

Customer :

ok i will try that. i suspect 12v to blue terminal and grd the other? or does it make a difference?

carguy1 :

It won't really matter out of the car. It seems like everyone is doing their job but the blower at this point

Customer :

any tricks on getting it out

carguy1 :

I think it is just three bolts and it should drop out for you

carguy1 :

Full Size Image

Customer :

i ran a jumper without taking it out and the blower worked

Customer :

re-tested white to ground continuity and checked out again

carguy1 :

Ok, I think I have taken you as far as I can without being there. At this point I would suspect a sensor. Temp sensor or something maybe or the panel itself not kicking things on. You could try the fan amp, but I can't promise it will solve the problem,

carguy1 :

I mean it seems to me that if you have power and ground the blower should work

carguy1 :

you just gave it power and ground and it worked?? makes sense right

Customer :

anyway you can send me schematics?

carguy1 :

There is no clear wiring diagram or I would

Customer :

i just tried jumping white from blower to ground and blew both fuses

carguy1 :

So that would make me think the blower is no good and shorting inside

Customer :

wouldn't it have blown the fuse initially if this was the case?

carguy1 :

This would, but I see no other explination to be honest.

Customer :

didnt you say that the blower gets it's ground from the fan amp?

carguy1 :

yep it does

carguy1 :

it has constant power

carguy1 :

I am going to open this back up for the other experts. Possibly one has had this type of problem

Expert:  Jay replied 6 years ago.
Hello and thank you for using JustAnswer.com

The most common for no blower motor control and the unit seems to work, is the Fan Control amp. Is that the part you replaced?

Let me know, thanks Jay!
Customer: replied 6 years ago.

Jay,

 

I have not replaced the fan control amp. I did however find a site online that explains how to troubleshoot it and it seems to check out ok. It is sending 12v to the blower but blower doersn't seem to be getting a good ground. When if jump the white wire on the blower to ground, it blows the fuses.

 

still a little leary of the fan control amp, it has signs of heat, but like I said it seems to check out.

 

 

Thanks for your input.

 

Expert:  Jay replied 6 years ago.
That is because the fan control amp grounds the blower motor. You most likely going to need the fan control amp. Here is part of the wiring diagram so you can see what I am saying. graphic


Thanks Jay!

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