I am experiencing a problem with my front turn signals on my 66 C-10. They are acting weird an hopefully, someone has had this problem and can help me out. My rear turn signals work fine. For the front (both left and right), they do not blink with the head light switch off or on fully. However, they do work with the light switch in the middle or park lamp position. Could this be a switch issue? Any help would be greatly appreciated. Thank you.