I had turn signals that stopped working but started after I applied the Hazard switch and turned it of. Doing that when the turn signals did not work kept the turn signals going for another 3 months.
When the turn signals stopped I replaced the hazard switch and the turn signals have worked ever since.

Other did not use an method of troubleshooting. It was just guess from the symptoms that the Hazard Switch seemed to wag the turn signals.

My Wife likes to thump her purse down on the Counsel. After replacement of the switch I told her she should stop doing that. But, don't know what she does when I am not there.

Note that it was enough years back that I don't remember if I read any threads on it and saw that other people were also saying there is a good chance it was the Emergency Flasher Switch but I don't remember reading about jumping the terminals.

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84 300D, 82 Volvo 244Gl Diesel