I have a 1999 Chev Suburban. Recently the turn signal relay has started to frequently click on its own as if I had activated the a turn signal. When the clicking starts, the turn signal lights do not blick and it seems to always stop when I apply the brakes. When I release the brake pedal, the clicking starts again. I have not had any recent electrical work done on this car. The normal turn signal fuction works properly. I’m suspecting a failing turn signal relay. What else could it be?
It’s probably the multifunction switch (turn, cruise, wipers). I had the same problem with my 2000 Blazer 2 years ago. The clicking was constant, but the turn signals worked normally.
Try spraying some CRC Electrical Contact Cleaner into the base of switch while working the turn signal to clean the contacts. This only stopped the clicking for a few days on my Blazer, perhaps you will have better luck.
Google “gm multifunction switch” for more info.