Check the wiring connections inside the front wings, bit of a bitch to get, had similar trouble with dip lights a couple of years ago, electrical connection spray done the job for me.
I've crawled all over this machine, however I cannot track down which relays are related to the lights. Globes OK, Fuse OK however not "juice" at the fuse or globe socket.
My REST heater is also not circulating coolant, so I'm wondering if there is a common supply gone.