Hello! My 2011 GL-450 started acting crazy after rain due to the ingress of water in the rear left quarter where a wire harness connector got wet. I found the water by removing the storage compartment where the first aid kit resides in the rear left of the cargo area. There was a pool of water there. The water wasn't coming in from my tail lamp seals, but somewhere higher up - I'm still searching for the location of the leak, but I've moved the wires up and keep the area drained after rain. The issue is under control but not yet fixed. Check that area.