pro user DRC4311 Manual page 42

Some modern vehicles with a monitoring function of the reversing lights (signal monitoring via PWM
Pulse Width Modulation and CAN of the vehicle, e.g. to detect a faulty light bulb or to regulate
brightness) may produce interference to the image transmission or even cause a total loss of the
wireless connection to the camera module.
In case your vehicle has this monitoring function, it might be necessary to implement one of the
following measures to restore the full functionality of your backup camera system:
1." Implementation of a PWM signal filter
These commercially available filters are usually put between chassis ground (negative pole)
and the positive power supply of the reversing light and the camera module. If you intend to
use such a filter, please follow the manufacturer's instructions.
Common trade names are:
„Reverse Backup Camera Power Adapter Filter" or
„Noise filter for pulsed reversing lights"
2." Usage of an automotive current relay
Another simple method to ensure the voltage supply of the camera module without an
interfering PWM-signal is to make use of a conventional automotive relay. The power supply of
the reversing light is used to trigger temporarily the relay (electromechanical switch), which
connects the PWM-free "ignition plus" of the vehicle to the positive wire of the camera module.
Contact
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Picture: A conventional automotive relay with standardized contact terminals
TROUBLESHOOTING
Description
chassis ground of the control current circuit
(negative-wire of the reversing light and the camera module)
+ positive wire of the control current circuit
(looped through supply of the reversing light)
+ positive wire to the camera module
+ voltage supply of the vehicle
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