1991-1993 240sx: Idle drops 100 rpm when interior fan is turned on

[vancouverbc]

It drops and stays lower until fan is turned off. If I turn on headlights it drops another 50 rpm. You would think the computer would just bump up the idle. The alternator is relatively new but has a bad bearing. I read 14 volts at battery when car running.

[Dittoz7]

Ok

[ricebike]

The alternator is relatively new but has a bad bearing. I read 14 volts at battery when car running.

umm yea your key words= bad bearing; common sense will dictate that it's causing the drag

get it replaced; most aftermarked rebuilds should have a limited lifetime warranty or if you got the cheaper version, a 1-year warranty or junkyard special up to 90 days

[vancouverbc]

I replaced the alternator but the idle still drops and remains dropped when heater fan is turned on. I think it is normal for the 240sx.

[NISSAN240SX12]

add another alternator to it! J/K.