Have an 03 Grand Cherokee Laredo. My left rear blinker is not working (regardless of if I'm using the turn signal or hazard lights or locking the vehicle). I replaced the bulb, but it wasn't burned out. When I do put my left signal on, the front flashes very fast.

Any ideas?

Thanks.

Yes, check the bulb holder for any signs of melted plastic. When they get hot, the plastic softens and the contacts loose their tension. Try swapping it with a reverse light holder to see if that's the problem. The bulbs are all the same, the holders are all the same. The difference is in the circuitry on the tail light assembly.