Replaced my brake booster and my brake light switch and the brake lights are staying on. Any idea why?

1998 gmc1500

 

Is the brake pedal up? My guess is the brake light switch is stuck, or the pedal is off the switch plunger.

 

all is installed and new switch. I’m dumbfounded

 

Do they go off when the brake pedal is depressed?

 

No, the brake lights stay on until the brake light switch is removed from the pedal, there's no adjuster on the switch just the spring on the inside.
I remove the brake light relay and the 3rd brake light on the cab stays illuminated

 

Do you have the original switch? If so, I'd suggest re-install it, new dose'nt mean good.

 

If it's not an ac delco switch I wouldn't trust it.

 

It can be the possibility of a faulty brake light or a switch blown.