I was driving my lr2 and heard load beep then all instraments went dead on dash, radio and rir still work but when i stopped and put in park throtle stopped working and can not shift out of park.

the dash lamp IMMO will not lie, it tells you if the key is good or now, covered in the free users guide.
but use the IMMO can lie of battery is near dead. sure.
not told what the gear shifter does,
what does CUT ON mean? (radio dead or works/)
the steps are easy cart like this auto transmission
we can crank the engine in park or neutral if we step on the the brake pedal, the lever moves. at your demand, called park lockout feature
I get it ,does nothing means the starter is 100% dead
while key turned (cranking) in PARK.
turn the key to on /run position the IMMO lamp talks to you now, it tells 2 things key good or key bad
if bad no immo car will ever start. or starts for 1 to 10 seconds and stalls.
if the battery is dead or failing many things will word and not work, for example radio works but the starter is dead the starter uses 1200 times more power than the starter.. so radios can work. with near dead batteries.
for 70 years true.
so, check battery lugs for rusty or loose
charge the battery and load test it.(in a shop)
or buy the tools.
or jumper cable jump the battery.
or call AAA auto club tow,and say jump start me car.

also learn that IMMO can lie to you if battery is weak.
answering for NO CRANK cars.

Sounds like the physical movement of the linkage is pulling or rubbing the harness. Get up under the dash and see how the harness is located.

the dash has a dimmer, this is dash park lights
and runs all radio back lights.
so if the dial is low, its dark
if the dash cluster glows good the dimmer is ok
and the wire to the radio called, dial

on after market radios its the orange wire. not 12v, its dead.
http://knowledge.sonicelectronix.com/car-audio-and-video/accessories-and-installation/wiring-harness-color-standards/

suzuki uses different colors.
turn on parks, with a voltmeter measure 12vdc at DIAL wire.
at radio.
0v bad, 12v good, if 12v then radio lamps are Blown out.

Check the battery cables for clean and solid connection.

it was a common prob with those cd changers in the boot/trunk disconnect it and let the head unit connect to it if still no good and the wiring/connectors are good the cd unit is faulty

Dead Battery

battery flat ,alternator not charging

I find it unlikely the Brake job had anything to do with everything else that just went wrong. They are almost totally unrelated. In fact the only thing that I can see that connects all the effected systems is possibly a safety feature through the ECM that prevents driving when there is a brake problem. You are really going to need a mechanic to look at this or at least someone with a scanner to read the codes before you even attempt to make a repair. Double check your brake fluid level to make sure it is full and that there wasn't a wire disconnected by accident.

check all fuses please

check your throtle cables and plate in throtlebody for opening & closing properly,