iThe safety valve alone
Knows the worst truth about the engine.
— From the poem “>Your Teeth Are Ivory Towers” (1940) by William Empson (1906-1984)
(According to critic John Holbo, that’s pretty much the best line in the poem.)
Affected trucks include model year 2008-2018 Freightliner Cascadia and Western Star 4700, 4900, 5700 and 6900 trucks. DTNA says after hard brake applications, the brake light pressure switch may not activate the brake lights with the light application of the brake pedal.