2017L83

I have this same issue now with my '17 sierra 1500. I had it before then it went away and is now back again with the cooler weather. I don't get how it could be the whole module if it just works perfectly some times. One would think if the LED was bad it would stop working for good. I haven't been able to find any differences in battery voltage when it is or isn't working, there is always power right up to the plug and I've swapped the control modules from one to the other before with no difference. Could a bad ground after the signal possibly cause this? Ive checked the one under the rad with no success. I can't believe they would make an entire headlight module that can't be serviced and want their customers to pay $1200 for a signal light .