I need help.

My car won't start when I turn on the ignition switch.

Every time turn the ignition switch, all my instrument panel went dead. There is no power at all. I used my DMM to check if my battery is good. I have about 13 Volts. I checked all my fuses and all are good.I disconnected my battery terminal connected it again. The power came on. When I turn the switch to start my engine, the power was off again. I disconnected the battery terminal and connected it again, the power came on again. I cranked my engine again, and the problem is still the same.

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