viper 300 disassembly

My neighbor have a 95 Nissan Altima with a Viper 300 alarm installed.
She never use the alarm,even she don't know where the remote is.
She did replace the battery 3 days ago,now the car some times flashes the lights and do not start, some times cranks but wont start without flashing the light.I believe all this is caused by the alarm,I like help her to remove the alarm (I'm a diesel mechanic).The switch by the Kick panel do nothing (I don't know how it work),I can see a transparent box under the dash with a red LED flashing if you tap on it (motion sensor?),so guys I really like to know what to do,before cut the wrong wire.
How I get here?? reading the black box with the wiring instructions and typing the serial number to find out was a Viper300,typed Viper 300 and this place comes out,amazing.I was thinking just reattach the spliced wires ,looking into the color code on the main harness of the car,just match color with color.what do you guys think?
Thank you so much.

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Suzuki Fan

The Key has to be turned to the on position in order for the switch to work.  You should be able to unplug the main harness from the brain.  This would disable the alarm.  I am pretty sure that the vehicle will start and run fine after disconnecting that unit.

If the vehicle does not start with the brain unplugged, there is only one wire that may need attention in order for the car to start.  At the ignition switch harness there is going to be a BLACK / YELLOW or a BLACK/ White wire that has been cut.  both of the cut ends will be joined to 2 wires that go to the alarm brain or to an outboard relay.  Simply reconnect this wire to it's original state. 

Guys I will try it on the weekend,will you keep posted on my progress,thanks a lot,this group really works.I's really amazing how fast the answer comes out.Thank you-

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Suzuki Fan