Quote:
Originally Posted by Roncallo
The foam tube is about $40.00. I dont know what it is there for.
John Roncallo
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John,
If I understand correctly, you are unsure of the reason for the tube? Perhaps you mean "...why foam...", but I'll continue for the sake of a greater audience. It is a duct for air to be drawn across the in-car temperature sensor. One end is attached to a hard line that is open to the fan compartment, and the other is attached to the sensor. As the fan runs, a bit of cabin air is drawn across the "aspirator" as it is called. This allows the sensor (a thyristor*) to sample the in-car temperature and adjust air temp and fan speed accordingly. I believe foam is used to insulate the "tube" from the under dash temp and more accurately sample the actual in-car air temp. On a convertible, this is academic as there is no way the sensor is going to read in-car temp; however, with the roof up, perhaps it does have a chance. Seems to me the air sampled will be influenced by the def output, so I fashioned a little hood to shield the temp sensor grill. Seems to work nicely.
Edit: The correct device type is a thermistor, not thyristor as indicated here.