Indicators not working

Have a 2005 c220 cdi. With the right side indicators not working on both back and front. The mirror one works though.
my first assumption was that it could be the front and rear SAMs, but it's it possible that they could both become faulty at the same time?
so far I've checked whether there's power coming to the lamp holder, and there's non.
From my knowledge, the front is controlled by the Same that suits in the engine compartment and the rear is controlled by the Sam that suits in the boot. Therefore the problem should be before it communicates with either of the SAMs.
anybody with suggestions as to where I should start?



