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Ouch, a new turn signal flasher relay is $65 at the local parts shop. Is it possible to DIY a repair of such a flasher relay?

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up vote 12 down vote accepted

Yes you can often repair turn signal flashers!

A variety of things can be wrong: here's one of them. Solder joints on the relay printed circuit boards are especially vulnerable to stress cracks, due to the clicking motion day in and day out.

Take the case off the relay and use a jeweler's loupe to inspect for hairline cracks, especially cracks those that go all the way around a pin that is shaken by the relay clicking. For example:

Bad solder joint on car flasher relay Stress crack in solder on flasher relay pins

To repair get a soldering iron fairly hot, melt the existing solder until it is fully wet, release cleanly, and let the solder form a nice shiny fillet. This is a very easy soldering job even for beginners.

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+1 for great use of pictures! Love that closeup. Macro lens or a really nice cell phone? lol – cdunn Feb 23 at 21:30
Nikon D40 with standard kit lens, @cdunn. I could take a better picture, but this better represents how subtle these solder stress cracks can be. – Bryce Feb 24 at 5:13
So does that crack go all the way through the solder (not just the surface layer)? – RockPaperLizard Jun 30 at 21:15

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