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radio lock out, but with aftermarket radio

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I recently purchased a used 2003 Sierra 1500. It has a JVC head unit that is not a factory installed item. Today I had to unhook the battery for an unrelated issue and when I hooked it back up I discovered that the radio is now locked out. I have searched around and found multiple posts regarding fixing this issue except they are all assuming a factory GM head unit is in the vehicle. Can anyone help me with unlocking my NON-factory radio? Thanks in advance.

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Google says that some of the JVC units have a master reset that will cause you to loose presets etc... If at that point it is still locked, you will probably have to call JVC.


model number of the head unit would probably help people answer your question.

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Sorry, should have posted the JVC model; KD-R740BT. I figure someone somewhere has changed from a factory radio in their truck to an aftermarket one and would have had to unhook their battery to do so and had this problem as a result.


Maybe locked is not the right word. After hooking the battery back up; the radio display will not power up. The cd player will attempt to eject a disk when the button is pressed but no response from any other function. I checked every fuse in the engine compartment as well as every fuse in the smaller dash compartment near the driver door hinge that had any discernible reference to radio, amp, or accessory.


There is the possibility that there is an in-line fuse somewhere else in the aftermarket system that I missed and will search for that but beyond checkingt fuses my electrical/ car stereo knowledge is pretty much tapped out.

Edited by Eric1371
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  • 5 years later...

You're having an issue with your radio being locked, or it doesn't power up?  Most likely, unless the manual for the radio describes some kind of "locking" UI, it's not locked.  It either isn't getting power from whatever harness adapter is used (or however the wiring harness has been hacked up), or the fuse in the radio has blown if it has one, or the radio has failed internally.

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  • 4 weeks later...
On ‎1‎/‎26‎/‎2020 at 5:02 AM, cmysstailights said:

Almost all aftermarket radios will have a fuse in back of the radio. Take it out and check.

Sent from my SM-G960U using Tapatalk

Here is the fuse diagram for the back of the JVC head unit.




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