Toyota Repair: Brake lights inop, turn signal switch, brake light switch

Question
QUESTION: I have a 1990 Camery that the brake lights do not work. Have changed out brake light switch but still inop.  Checked voltage to wire off switch has 12V but when switch or jumper wire plugged in the circuit shows to have a ground what was once the power side  Can you shed some light on subject possible problems with turn signal switch?          Thank You Phil

ANSWER: Can you tell me which wire color shows 12volts and which shows ground with the brake pedal not depressed.

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QUESTION: The green wire with a white stripe has voltage with the brake switch disconnected and the solid green and the green wire with the switch or jumper wire connected both show to go to ground.

Answer
This should also blow the stop light fuse, has it been checked, if it is blown then it would confirm the short circuit that probably exists at the rear brake/tail light sockets, disconnect the tail light wires completely from the wire harness and see if the fuse still blows, if it stops blowing then the problem is a short cicuit in the brake /tail light assemblies.