I don't think ALL the lamps can be out, the cruse unit checks for ground on the brake light line, when that ground goes away it assumes the brake pedal is pressed and the lights are on. Having all the lamps burnt out causes the same thing.

-Jason

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.