Brake switch changed, still no light??

[deacon]

about 12 months ago The brake light switch failed, Glow plug light Flashing, ABS & ESP Light on
Same thing happened again on weekend, so I changed the switch but the dash lights etc remained, not brake lights.
I stripped the old switch & it all seems fine,
It could be coincidence but at the weekend I was towing a car on a trailer, the ABS & ESP Lights came on then, the glow plug light came on after about 30mins driving, which leads me to think it's more than the brake switch.

I am reluctant to take to a garage, so hoping you guys could shed some light.

Mucho Gracias