My m3 ever since purchase doesn’t turn on properly, lost its program.?
Have you tried cleaning all the threads and making sure that the retaining rings are screwed down tight?
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Here’s an oldie but a goody:
Yeah, first clean everything with some alcohol and q-tips. The contact ring on the driver, the positive post or spring in the head, the bare metal parts of the tube on both ends, the spring in the tail cap, the contact /retaining ring around the switch, the battery plus and minus ends. Make sure the retaining rings in the head (for the driver) and tail (for the switch are snug. Maybe loosen them a bit, then tighten them back up snug. Make sure you battery is fully charged. If you can see any obvious corrosion on any part, try cleaning it with a pencil eraser, then alcohol. As in the linked post, you can use either very fine sandpaper or a file to GENTLY clean the ends of the tube. Not to remove much material … just to clean it a bit.
The idea is to make sure there is good electrical contact through all parts of the light.
OK, this is quite close to what the linked article says it is just a bit more condensed…and maybe a bit easier to follow… fewer words, less steps. Non-linear troubleshooting… like the shotgun approach… 
If this is all good, you could have a bad switch, driver, or LED. But troubleshooting for that comes next in the process. Let us know if this helps.
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For the record, Convoy will send you any parts to repair your light. Not free but certainly cheap.
@Wyau321
If it never worked, which I think is the situation for your light, he will either send a whole new light or parts to fix the broken one at no charge… Just contact Simon Mao through his AliExpress Convoy store or here via PM.
Still good to take care of all of the easy stuff first!
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Convoy m3 not going into high mode
Is the battery in it fully charged? Do you have any way to see what the voltage is?
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