If the user can't find the manual, maybe suggest general trouble-shooting steps for car radios. Like checking power supply, fuses, connections, common error codes, etc. But note that without the specific manual, detailed troubleshooting is limited.
If the user can't find the manual, maybe suggest general trouble-shooting steps for car radios. Like checking power supply, fuses, connections, common error codes, etc. But note that without the specific manual, detailed troubleshooting is limited.