That small fan is called an aspirator blower. It samples ambient cabin air to tell the AC what the temperature inside the car is. You can verify if it is still working or not by placing a small square of tissue paper over the vent. If the fan is working properly it will cause the tissue to stick there.

It could very well be the reason your main blower has slowed down. If the AC system thinks the cabin is warm/cool enough it will slow down the main fan to where it is barely running.

A couple of easy tests:

1. Use the manual fan speed buttons and turn the blower on to maximum.

2. Set the temp controls to all the way hot or cold.

If the blower speeds up then the regulator/motor are probably OK.

If you failed the tissue test above, replace the aspirator fan and things should start working again.

If you can't remember the last time the pollen & recirculation filters were replaced then it's time to do them. They can have a big effect on the amount of air the AC system can move.

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"It's not about how fast you can go, but how well you can go fast."

Bob in Richmond

'97 S320 (LWB), Ruby Red Metallic, 73k miles
'97 S420V, Smoke Silver Metallic, 155k miles