I have a 2012 Grand Cherokee Laredo completely stock (92000 miles). The past several months the rear left turn signal bulb stops working. I pull it out and it starts working again (same bulb). About a month later it did it again. I replaced bulb with a 3057 bulb. Three weeks later it goes out again. This time I replaced it with a brand new 3157 bulb. Worked fine for about three- four weeks then stopped working again. This time the bulb was actually burned up. I just pulled the socket apart and don't see any corrosion or evidence of a short. Wiring looks good. Any idea what might cause this or what I should look for?