Left Taillight driving lights not working?

All of a sudden my left driving taillights are not working. The left rear turn signal works. The left rear brake light works. The left rear backup light works. But the top 2 lights should come on when I turn on the driving lights and they don't. So, in summary, all 3 left rear light bulbs work individually but the top two bulbs do not come on when I turn on the driving lights. All three bulbs on the rear left are the same model and are brand new. Ive checked all the appropriate fuses are they're good. What else could it be?


thanks.