Blower speed slowing down at idle

[Jstawgn]

Just notice my blower speed is slowing down quite considerably at idle. It pick back up at normal cruising RPM. What would cause this? Alternator going start to go out or battery getting weak? It was about - 7°F this morning. I did start hearing some screeching noise when cold near the alternator / power steering area. Just have not been able to pinpoint it yet.

Battery is autozone duralast gold fresh this spring courtesy of PO. Truck got 162k.

 

[ADVFamilyHauler]

Just notice my blower speed is slowing down quite considerably at idle. It pick back up at normal cruising RPM. What would cause this? Alternator going start to go out or battery getting weak? It was about - 7°F this morning. I did start hearing some screeching noise when cold near the alternator / power steering area. Just have not been able to pinpoint it yet.

Battery is autozone duralast gold fresh this spring courtesy of PO. Truck got 162k.

I am having the same issues minus the screeching noise. Did you ever figure out the problem?

 

[Jstawgn]

Haven't got this cold again until yesterday and today. The truck is currently down in the garage waiting for new rear brakes.

Battery have cold cranking amp that are much lower thank warm cranking armp. CCA is rated at 0°F for 30 second and need to be ale to maintain at least 7.2 volts. I imagine 12 volt motor would not be very happy at 7.2 volts.