Info ref the blower and how it’s controlled


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The blower is installed in the air inlet duct, below the cabin air filter, and consists of an open hub, centrifugal fan powered by an electric motor. Operation of the blower is controlled by the ATC module, using the blower relay in the battery junction box (BJB) and the blower control module. The blower control module is installed in the air inlet duct downstream of the blower, where any heat generated during operation is dissipated by the air flow. A wiring harness on the air inlet duct connects the recirculation door motor, blower and blower control module to the vehicle wiring.
When the blower is required, the ATC module energizes the coil of the blower relay. The energized blower relay supplies battery power to the blower motor, which is connected to ground through the blower control module. The speed of the blower is controlled by the blower control module, which regulates the blower motor voltage in response to a pulse width modulation (PWM) signal from the ATC module. To vary the blower motor voltage the ATC module
varies the duty cycle of the PWM signal.
When the blower is in the automatic mode the ATC module determines the blower speed required from the comfort algorithms. When the blower is in the manual mode, the ATC module operates the blower at one of seven fixed speeds as selected on the control panel.

Automatic System Control Panel Connector plugs

Please let me know if u want an electrical diagram

Hope that helps

Gary

gstuart said:

Hi

The sport from 2005 to 2013 is a L320 , from 2023 it’s a L494

Have u first tried the self test , heres how it’s done

Here the self test procedure:-

"With ignition off press and hold the ECON & RECIRC buttons whilst turning ignition on (no need to start car).

The control module will then compare the current HEVAC actuator motor positions with the values stored in the module and will indicate an error by flashing the ECON LED.

If there are no errors, the LED will go out and the system will function normally.

To confirm that there are no errors, turn the ignition switch to the OFF position, then back to the ON position.

Observe the operation of the programmed defrost LED.

If there are errors present, the programmed defrost LED will flash and the system will attempt to calibrate itself."


See how u get on, if still nothing Plse let us know , I’ve got a D3 so virtually the same setup and can go from there

Assume you’ve tested the fuses , will the fan work on manual or auto plse, or completely dead

Click to expand...

Thank you for this information I will try in the morning and let you know results!!

Gman123 said:

Thank you for this information I will try in the morning and let you know results!!

Click to expand...

Ur very welcome , thought then at least u have some info to make a start, with a multimeter, ie testing relay, power to the fan etc ,etc

Indeed please let us know how things go

gstuart said:

Ur very welcome , thought then at least u have some info to make a start, with a multimeter, ie testing relay, power to the fan etc ,etc

Indeed please let us know how things go

Click to expand...

gstuart said:

Hi

The sport from 2005 to 2013 is a L320 , from 2023 it’s a L494

Have u first tried the self test , heres how it’s done

Here the self test procedure:-

"With ignition off press and hold the ECON & RECIRC buttons whilst turning ignition on (no need to start car).

The control module will then compare the current HEVAC actuator motor positions with the values stored in the module and will indicate an error by flashing the ECON LED.

If there are no errors, the LED will go out and the system will function normally.

To confirm that there are no errors, turn the ignition switch to the OFF position, then back to the ON position.

Observe the operation of the programmed defrost LED.

If there are errors present, the programmed defrost LED will flash and the system will attempt to calibrate itself."


See how u get on, if still nothing Plse let us know , I’ve got a D3 so virtually the same setup and can go from there

Assume you’ve tested the fuses , will the fan work on manual or auto plse, or completely dead

Click to expand...

Thank you for all your help seems I was lucky this time swapped the fuse now working again!!