I have 2012 CTS4 Sport Wagon (export model). Rear fog lights stopped to work after car battery was failed (worked fine before that). I can see via Tech2 (BCM ext. module) that there is a switch and lights for rear fogs, but I cannot turn those on from Tech2 nor the real switch. No error codes found from BCM. Fuse (in rear compartment box number 18) is ok. Any ideas where to start to solve this issue?
Thanks for the update--better late than never.
When you say multifunction switch, are you referring to the turn signal arm on the steering column?
I'm unclear as to where the rear fog switch is on export models.