whats next replaced brake light switch

test voltage at the switch....

get a NEW battery....wirebrush the end of the cable that attaches to the chassis/fender....get it nice and clean and ready for the 300 cold cranking amps....BTW your ignition and ECU....and windshield wipers also use this ground....it IS important~ this level of amperage "welds" this connection with every use eventually creating a "brown power" condition~~~a coarse wirebrush....a bolt and a bit of tidying up and off you go~

just trying to make sure that your lights and accessory devices have the SOLID power that they need to function correctly~

ck fuse #3 in fuse box under the hood. does only the 3rd. brake lamp work? If so, the brake switch input goes back into the tipm(totally integrated power module) The tipm will turn on the brake lamps when it sees an input from the brake lamp switch. Ive seen where you have to use the starscan(chrysler scanner) to erase tipm codes. The tipm can act like a fuse. when codes are erased, lights work again. hope this helps......