brake switch

I just installed a Carvox remote start/keyless entry for a friend first off this unit has the worst directions I have ever seen.   anyway here is the problem everything is working great except for the cutoff switch on the brake pedal. It is hooked to to the switched pos. on the switch as directed and tested and verified but the start does not cut out when activated.   My question is this is it possible I need to hook into the neg side of the switch instead as I believe this is a neg switched circuit as most other ones are on this vehicle (Toyota). any help would be appreciated.

It is 92 Toyota Land Cruiser.    The wire does have 0 volts till pedal is pushed then 12 volts when depressed via fluke dmm.   Tried running the wire to known 12v + and still no shutdown.   Hope this clarifies.

ghetto rig 101 is now in session. if your brake shutoff wire wont work try using the hoodpin wire with a relay to change your positive input from the brake switch into a negative that your hoodpin wire uses. do this only if replacing the brain is not an option though

I will look at it again tomorrow.   this unit was bought a year ago or so doesn't look promising to return brain :(.   Hopefully i can come up with something since the rest of the system works fine, i have yet to try a ground signal to it so I might try that don't have much to lose at this point as it seems as I thought in the first place a brain problem. Thanks for the input.

i got  that  problem  with this  remote starter  the  starter dosnt shut off when  the brake presst  just  press  the brake  tow times and will shuts off