HELP!!! Wife locked keys in car!!!!!

[robertsafc]

Hi, hope some one out there can help me, wife has loked keys in the boot of her ford focus, t reg.
I am a tech for mercedes benz, and i have a friend who told me if i short the high level brake light out the boot will open, tried and it did not unless im doing something wrong, please let me know if you have any ideas without and damage involved.
thanks
rob