Heater blower motor fan on 2006 Nissan Altima making noise

Hi Tina,could be your blower motor resistor,it's located next to the blower,2 screws hold it on,remove electrical connector first,take to Autozone and get a new one,if it doesn't fix,they will take back and refund your money Tina.here's a link to the resistor Tina. Duralast Heater Blower Motor Resistor JA1219 at AutoZone com Here's a link showing you the resistor Tina. Repair Guides Blower Motor Removal Installation AutoZone com

sounds like a mouse attack to me. mice get into the heater vents and blower motor cage and make nests. those can throw your blower motor out of balance, thus resulting in the noise and then the motor just gets jammed and stops operation. but it could be just the blower motor failure it self. have it checked.

The cooling and heating fan for the interior is located under the dash on the passenger side.

Not the core making noise it is most likely the blower motor or the fan cage attached to the blower motor... most blowers are attached under the dash on pass. side or under the hood at the pass. side firewall area attached by approx. 5/6 #8 metric small bolts opr 1/4 inche or the like, it has a small black vent hose attached to it that also needs to simply be pulled off ...this will give you an idea where the blower is, the fan cage once you pull out the blower and disconnect the electrical plug and ground wire is mounted on the blower motors shaft with a #10 or a 3/8 inch or the like nut retaining it on the shaft.

either theres leaves or rubbish in the fan(it can get in there)or the fan is worn and needs replacing,under dash,sometimes the noise will go as the leaf clears

The blower resistor has gone bad and needs to be replaced, it's common for it to burn out due to time. You can pick one up at Auto Zone and they will have the step by step instructions to replacing the resistor. 
The blower motor resistor is under the dash, next to the blower motor. You will need to remove the under dash panel to access it. It is very easy to replace, just two screws hold it in. May take about 15 to 20 min with simple hand tools. 

Good luck and hope this helps. 

I've had mice in my Nissan PU and actually caught one in a trap set on the floorboard; so I know they can get inside. They also knocked some of the fiberglass insulation into the blower motor so it vibrated as it was no longer balanced. You could have a dead one in your blower. Mine was easily accessible from under the passenger side under the dash. Three screws and the motor dropped so I could clean out the fiberglass.

Resistor switch. The rotary switch on the dash is very, very uncommon. It is also not the blower, because it works.

you need to remove your glove box assy.(beleave only 2 screws and pivot clips) make sure its not anything from glove box that has slipped behind. once box is out uf way you can access easier the blower motor assy. it actually attaches into blower box from bottom side. when looking at you will find three screw/bolts fastening motor to casing. remove those and then slowly lower motor and fan cage(attached to motor shaft) out from housing. sometimes it takes a little convincing to come out but not real tough. once out you most likely find the object causing noise in fan cage or resting up on lip area of housing unit. once found install in reverse order. let me know if this helps or if we need to dig a little deeper into! good luck!
joel

yes, but not without a lot of difficultly.