Check your signal flasher on the Multifunction switch. It is the likely culprit. I had the same problem last week. It started off with the signal working a few times and then stopping for one side, then got progressively worse for both right and left. Then the hazard flasher stopped as well unless I pushed the switch up and down a few times, or put the headlight high beam switch on and off a few times or put pressure on the signal stalk. I removed the switch a couple of times and carefully dis-assembed it with a couple of small screwdrivers making sure not to break any tabs or lose the springs or the Hazard switch toggle wire. the copper conductors in the switch are very robust and only showed minor wear. Copper is very conductive so it would take major corrosion or a very worn copper part of the switch to be a switch problem. I replaced the old grease with new after cleaning with electrical contact cleaner. The switch would work for the next day and the problem would come back. i got some success by squeezing on the flasher and partially removing it from the socket on the switch. However eventually problem came back. Sometimes it would work, sometimes it would not.
If you use a meter to confirm the electrical paths on the switch with the flasher removed you can discount the switch itself.
The intermittent problem which turned into a constant one turned out to be a failing solder connection on the flasher electrical board. If you carefully pop off the flasher cover with a small flat screwdriver and inspect the circuit board under a large magnifing glass without touching the surface mount components or chip you will likely notice a crack in the solder on the connection for one of the main spade connectors for the flasher. It will be in one corner. I soldered mine back and all problems disappeared. I have a photo showing the problem and can post it tonight. I suspect that the mounting location on the steering column makes the flasher subject to continual vibration from the drive train and eventually breaks one of the solder joints. With 264,000 KM on my car it was just a matter of time
