For double-din radio with 1J0 CCM, the cluster sends the dimmer info over the CAN bus to the radio.
Does not matter double-din or single-din. CAN-bus in radio used only from September 2000. All radio installation (in original) before this date used separate wire for dimming. See schematic in ELSA.
I added a newer Immo3 cluster and newer double-DIN radio to my car. I added CAN bus wires between the cluster and radio.
This is a custom installation. Not original wiring.
I suspect that ColorMFA is only looking for dimmer messages sent from the CCM to the cluster.
CCM does not send any info about brightness. Only cluster do this.
Checking/unchecking "manual" brightness doesn't seem to have any effect.
Automatic brightness in this cars work only if any lights is on. If your light switch in Off position automatic brightness not working.
Does not matter how you connect your radio. ColorMFA get info about brightness from Motor-CAN (firmware b25 and newer).
In CAN-monitor see message with ID 420, byte 6.
Добавьте данные об автомобиле в подпись (профиль -> подпись). Чтоб не спрашивать постоянно... :)
Please add info about your car to you signature (profile -> edit signature). To not ask every time... :)