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Trick to tell if recirculate air button is working?

button doesn’t light up anymore. how can i tell if its just the light and its actually working vs. it is not doing anything? i.e. how can i test where the air is actually coming from?


With the blower off and the car at speed a more air will blow in the vents when the button is on fresh than recirculate.

Or you could just sit still running the A/C on fresh air for a bit with the blower on high then set it on recirculate and it should sound like the blower started moving twice as much air and it will also feel like there’s a bit more air coming from the vents. Of course you’ll have to do this with the engine running.

Another method–albeit not the healthiest one–is to drive in back of a smoke-belching diesel truck. If you are able to keep out most of the smoke and fumes, then the recirculate function is still working. If you are unable to block the entry of most of the fumes, then it is not working.

With recirc. on and the windows up, you should start feeling the air in the car getting stale and more and more humid. The more people in the car the quicker you should notice. The windows will also start fogging up inside.

You could identify (through a diagram) what motor is suppose to move what flap when the switch is pushed and then watch for movement when activated. Most higher quality manuals contain a diagram of the HVAC housing with a description of what motor and lever does what. What kind of car are we talking about, I will see if I find a diagram.

I find that the fan noise increases on the Silhouette when we turn recirc on.