How to check a unit that doesn’t turn on?

Technical Advices for Specific Questions / Functions

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How to check a unit that doesn’t turn on?

Postby xtrons » Tue Jan 10, 2017 6:44 am

Generally speaking, XTRONS will provide you with the standard ISO cable or custom ISO wiring harness to power your unit on. But sometimes, the unit does not turn on when installing it for the first time or after having used it for some time.

Situation 1:
For the universal unit with ISO power cable.
Please first check whether your car has a CANbus system which controls your original radio’s turning on or off. If your unit doesn’t have the CANbus system, you just need to make sure you have connected the Red, Yellow and Black wires correctly, and then the unit will turn on automatically when you start your ignition key.
ISO.jpg (66.6 KiB) Viewed 29690 times

Yellow Wire: Connect with your car battery to get 12V permanent power supply.
Red Wire: Connect with your car ignition (ACC) wire.
Black Wire: Connect to the Ground.
If your car has a CANbus system, but you bought an XTRONS universal unit without a CANbus, you may need to buy a CANbus adapter (for example from connects2) or modify the wires to make the unit work with your car.
Please make sure that the power harness on the car stereo side has been connected tightly, and the blue fuse in the back of the unit is in good condition.
There are some units which need to be turned on with a power button, as not all units can turn on by the starting of the ignition key.
Sometimes the button may get stuck and as a result the unit may not turn on so it is worth to check this.
If you have excluded all these possible situations, and the unit still does not turn on, please try to remove the unit from your car and test whether there is 12V to 14V power supply from the Red and Yellow wire.
You can also try to install your original car radio and check whether a power supply problem exists.

Situation 2:
For the unit which has a power cable with CANbus box, such as some VW, BMW, Mercedes etc.
In some cars, the original radios' turning on or off are controlled by the CANbus system, if you buy an XTRONS vehicle specific head unit, it will come equipped with the required CANbus box to decode the ignition signal.
If there is something wrong with the CABbus box, the unit can’t be turned on normally. You can try to remove the CANbus box, and try to cut the red wire and connect it with the yellow wire.
If the unit can turn on after you modify the wire connection, but the steering wheel control function cannot be used, you can choose either connecting the red wire with your ignition wire (in this situation, you can’t use the steering wheel control function) or contact us for a new CANbus box.

If you have any other questions, please feel free to leave a message on the forum or contact XTRONS support via

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