On a somewhat regular basis, I get an error message that my RR Turn Light is out. It's not. I turn off the key, re-start the engine and suddenly my LR Turn Light is out. (It's not either). I re-start again and its back to RR Turn Light out. After a couple of tries, the problem clears and works normally for a week or two then it happens again. My rig is wired for towing behind my motorhome, and I installed diodes to run the lights from the motorhome. I've checked the wiring, and everything is clean and connected properly. Any suggestions on what else I might check?