2000 S70 Fluctuating Fan Blower Speed

USN Smitty · Post by **USN Smitty** » 09 Mar 2014, 10:10

Recently the fan blower will fluctuate speed regardless of the position of the fan switch. This occurs in both defrost and when blowing ambient air. The fan initially responds to the speed set by the switch but after a few minutes it will begin to slow or vary speeds and finally stop blowing completely. If I turn the fan speed off for about 5 minutes it will repeat the cycle. I had the car charging system checked and the alternator appears to be producing good power. Another odd thing is that this slowing of the fan does not appear to happen when the key is in accessory position, only when the car is running. Could it be the fan resistor or motor itself?

Post by **rspi** » 09 Mar 2014, 12:04

Hi and welcome to the forum.

My guess would be the blower motor is going out. Does it squeak?

Do you have MCC or ECC?

USN Smitty · Post by **USN Smitty** » 09 Mar 2014, 12:15

ECC, some squeak when the motor slows or begins to lag. Squeak not continuous as sometimes it is very smooth.

Post by **Ozark Lee** » 09 Mar 2014, 13:09

If it is squeaking you need to oil the bearings. If you let things continue it will eventually take out the power stage (blower resistor) and they are quite expensive. When the motor bogs down and squeaks it is drawing considerably more current than it does normally.

...Lee