When I have 4 way flashers on and hit the brakes the flashers stop working. Is this normal. asking because I changed the wiring harness.

1968 Dodge Charger

 

From what I remember, that is normal behavior.

 

Rusty, This trick works on some mopars. With the key off, the 4 ways on, turn signal on, and your foot on the brake. Your radio will work. The power will backfeed from the 4 ways through the turn signals and energize the accessory curcuit.