"turn switch" is the topic here. Very easy procedure.
In my case, I found that the turn switch can be repaired by following these instructions with a slight modification:
Left Signal Issues
I tried the above without the below modification and it only made the turn switch worse.
The modification was that I added a very thin layer of solder to the middle contact - the middle contact was worn. I used a bit of MAF cleaner to first clean the contact before I soldered. You don't want to screw the turn switch back on until you've tested the turn switch first.
I also recommend to the above link that you find and unscrew the
right screw from below (it's below the keyhole) to release the
upper plastic panel, though you don't need to take off the plastic panel. There's two screws that hold the turn switch in place for the corolla 99.
do not be tempted to buy cooper anti-seize grease to give better electrical conduction as I was attempted to do as it may short circuit the other wires. I believe so long as a thin layer of solder can be applied to the middle contact, then dielectric grease is good enough. This will save you $125 from buying a 3rd party turn switch or upto $500+ from dealer.
some people say that it could be the flasher unit. For me, if the turn lights sometimes work and sometimes doesn't, I personally believe that the flasher unit is good. It's worth the easy effort to follow above link to take apart the turn switch yourself first.
Here's the thread I originally embarked on which talked a little about the flasher unit but didn't explain how to troubleshoot which component would go bad:
Turn signal
if you need more info, do an advance search for "turn switch" but I think the above will fix the issue.
Linear Mode
