Whirring hum noise tracked down! Temperature 32c
Posted: Wed Nov 30, 2011 5:13 pm
OK probably not the most critical pieces of information ever needed But for the last few months we have been hearing a little whirring hum noise coming from the dashboard area on the passenger side, nothing critical could only be heard with the engine off but with the Ignition on, just detectable during quiet pieces of music with the radio playing.
Turns out to be the Cabin Air Temperature Sensor, its a little PCB with a small centrifugal fan on it and a chip to handle the sensor (thermistor) which feeds the Digital Air Con. electronics.
The centrifugal fan draws air over the sensor from the cabin and runs all the time the Ignition is on, it had just become excessively dusty over the years sufficient to make the noise!
The module can be released by a single screw just underneath it which locks the bracket in place that holds the module and unplugging the cable, easy to remove, a little fiddly to put back as it has to be done be feel.
The module top is held in place by 4 small screws that can be released to give the whole unit a through dusting from the inside which has reduced the noise a lot, might however just put a very tiny drop of oil on the bearing to fully quieten the noise down.
Edited so it can be found more easily in a 'Search'.
Heater, digital, temperature, 32c, cabin, fan, footwell
Turns out to be the Cabin Air Temperature Sensor, its a little PCB with a small centrifugal fan on it and a chip to handle the sensor (thermistor) which feeds the Digital Air Con. electronics.
The centrifugal fan draws air over the sensor from the cabin and runs all the time the Ignition is on, it had just become excessively dusty over the years sufficient to make the noise!
The module can be released by a single screw just underneath it which locks the bracket in place that holds the module and unplugging the cable, easy to remove, a little fiddly to put back as it has to be done be feel.
The module top is held in place by 4 small screws that can be released to give the whole unit a through dusting from the inside which has reduced the noise a lot, might however just put a very tiny drop of oil on the bearing to fully quieten the noise down.
Edited so it can be found more easily in a 'Search'.
Heater, digital, temperature, 32c, cabin, fan, footwell