my e38 caught fire when a headlight bulb cracked and shorted, on the uk model '97 728 there is no fuse on the front lights as far as i can find the loom caught fire quickly followed by the headlight plastic and inner arch. I was lucky i keep a fire extinguisher in the boot and a smaller one under the seat since i had an e30 catch fire from a split fuel line back in the 90s. only 2 car fires I've ever been involved in or had any first hand knowledge of and both bmws.
I bought a loom, inner arch, light and some other bits from a breakers and fixed up the 7 but spliced in some fuses, what a terrible piece of electrical design it wouldn't surprise me if the e53 has similar issues being closely related to the e38.
BTW: dont ignore the "check low beam" message
