2014 Silverado in morning no left turn signal later in day works just fine. Seems like something warms up and it starts working. Sets up over night and stops.
A faulty multi-function switch can cause that problem.

Tester
2014 Silverado in morning no left turn signal later in day works just fine. Seems like something warms up and it starts working. Sets up over night and stops.
A faulty multi-function switch can cause that problem.

Tester