Brake lights stay on

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1972 Mach 1 Q Code
I pulled my car in the garage and the brake lights stayed on. I have a relatively new brake light switch and turn signal harness. Looks like the switch is moving properly when the pedal is depressed and when I have the car running all the other lights are working properly except the brake lights. It figures that I am supposed to go to a car show in the am,😡. But oh well, I will just be happy to figure it out. Any ideas? I‘d appreciate any help, electrical problems are not my easiest things to fix. Thanks
 
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1971 Mustang Sportroof M code
Make sure your emergency flasher button isn't in the "On" position. Check both the turn signal switch and emergency flasher switch by activating them, make sure they are functioning correctly. The brake light switch, turn signal switch, and emergency flasher switch are all interconnected.
Disconnect the brake light switch wires from the switch, see if the brake lights go out. As has been said many times on this forum, New does not mean proper function.
 
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1972 Mach 1 Q Code
Make sure your emergency flasher button isn't in the "On" position. Check both the turn signal switch and emergency flasher switch by activating them, make sure they are functioning correctly. The brake light switch, turn signal switch, and emergency flasher switch are all interconnected.
Disconnect the brake light switch wires from the switch, see if the brake lights go out. As has been said many times on this forum, New does not mean proper function.
Thanks Don, I will try in the morning. I was trying to un plug the switch wires, but couldn’t do it, long day to tired.
 
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Ok so I found out that the brake light switch is bad. I unplugged it and the lights went out and I plugged back in and lights stay on. It even made my hazards not work properly. I have an old switch, plugged it in and everything works properly. I had put the newer switch in cause the little tab that holds the plug on had broke. I can use this old one for awhile till I get another new one.
Thanks again Don, I really appreciate your help! I never had this problem before but now I know what to look at if it happens again.
 
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1971 Mustang Sportroof M code
Ok so I found out that the brake light switch is bad. I unplugged it and the lights went out and I plugged back in and lights stay on. It even made my hazards not work properly. I have an old switch, plugged it in and everything works properly. I had put the newer switch in cause the little tab that holds the plug on had broke. I can use this old one for awhile till I get another new one.
Thanks again Don, I really appreciate your help! I never had this problem before but now I know what to look at if it happens again.
You're very welcome. When I saw your post about waiting to unplug the switch, I knew exactly where you were coming from. The old pressure switches on the master cylinder were a lot easier to get to, but became impractical on dual master cylinders. Therefore, we have to contort our bodies, that don't bend so good anymore, into pretzels.
 
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My all time favorite vehicle is our 1969 Shelby GT500
I found there are two different brake switches for 71-73 mustangs. One for power disc brakes and another for drum brakes. I have the wrong one in our 73 Mach 1. It CA and with drum brakes. Prior owner replaced with mustang power front disc brakes and related master cylinder. Did not replace the brake light switch. Light applications of the brake will not light up the brake light. Heavier applications of the brake pedal is fine. I ordered the correct switch and plan to change it out ‘Soon.’ I may be good for you to do the same.
 
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