s14 heater/ac problems-fan rattling, & doesn't work on 4...

[dosborn]

i've got some pretty bad heating/ac issues on my 95 240... first the darn thing doesn't blow on anything except 4. if i'm driving down the road, and i turn off the recirculate button, i can get airflow through the vents, but once i turn the recirculate button on, i get nothing. also, when it's blowing on 4, the thing is EXTREMELY loud because of a rattling coming from under the right hand side of the dash... any idea what my problem might be? i've been lurking on these forums for quite some time, and you guys seem to know more about these cars than my freakin mechanic, lol...

[Outlaw240]

The problem with fan only working on speed 4 is due to a little item called a "Blower Motor Resistor", it is what regulates the voltage that goes to the fan to control the fan speed. The rattling sounds like the actual blower motor/fan is close to be needing replaced.

*edit*
Just checked at work for part number and pricing:
Blower Motor Resistor - Part# 27150-41B00 - Cost $21.65
Blower Motor Assembly depends on production date:
2/94-5/94 - Part# 27220-70F00
5/94-current Part# 27220-70F01 - Both Cost $199.17.
These are retails from the Nissan dealership I work at...I have teh funness of working in teh parts dept :D
*edit*

The reason you get airflow through your vents with the recirculate "off" is due to the air gate/dam is open to allow fresh/outside air into the system which would also allow air to flow through without the fan blowing. With the recirculet turned "on" it closes that gate/dam to allow the A/C system and/or the heater core to due its job effieciently.


Hope this answered your questions,

Mike

[dosborn]

mike,
thanks a lot for the quick and helpful response. a few more quick questions...
are the blower motor resistors hard to put in, or would i need to take it in to a shop?
also, being a broke college student, $199 is a little steep.... would a used motor from a junk yard be sufficient and worth the effort?
thanks,
derek

[Outlaw240]

A used blower motor should probably work fine as long as it doesn't have any problems of its own...but at the very least, it would probably be quieter and alot cheaper than a new one.

The resistor goes in the side of the blower motor...I will see if I can get a picture of my diagram posted...it should be held in place by a few screws and should slide into ist slot. Its kinda half credit card sized, but is like a computer board. Hardest part is getting to it, which is simplified by removing the glove box to get to it.


Let me see if I can get that diagram and post it.....

*edit*
bah...I have a remote connection into my office at work, but the modem/router seem to be down at the moment...I will try to get it later today if I can...hope the description at least points you in the right direction for now...
*edit*

[dosborn]

it sure does, mike.... thanks again! i'm gonna try and pick up the resistor this week... might be a while for the blower motor, though. how hard are the blower motors to install? it's not something i would have to pull the dash on, is it?