front blinkers do not work but the bulbs are not blown and the fuse is not blown

Hello, When this happens there are several things it can be, and all of them should be tested. 1- both bulbs could have failed. Remember that just because they look good, does not mean they are. There are two filaments in the bulbs, only one is a turn signal. 2- the sockets for the GL W164 chassis turn signals have been found defective more than a few times, so the current for the turn signals may not be making it that far. 3- the power distribution box (underhood fuse panel) may have the answer in the form of a bad fuse, but if not, you may have a faulty front SAM (Signal Acquisition and Actualization Module). I guess they should have called it the SAAAM instead. In this case, I would check the fuse first, then check for power at the fuse, working my way back to the SAM if there is no power, and to the turn signal if there is power.