Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Hello,Either one of the bulbs has a short circuit, or the SAM module ( it controls all of the exterior lighting) has failed.
I suggest to pull out all of the turn signal bulbs and reverse lights one by one to check if then lighting starts to work properly. It is important to turn off the ignition and lock the van, for the SAM module to reset.
If this does not help, it is possible to diagnose the issue with Star Diagnosis computer.