I have problemes with a robot! please help me

hello! sorry I can make a query? I'm putting together a line following robot with an Arduino Uno r3, 5 CNY70 sensors and an integrated circuit L293D at first everything worked perfect, sensor measurements which were so true, then no longer know what happen to the arduino LED, the light become more tenuous and now sends me random numbers in the serial monitor trought analogRead, I thought was the Atmega328, but today i bought another one. the same thing keeps happening. what can i make? i read about floating input and then i put resistance to earth and keeps coming out the same only with many 0 at random, someone could give me some advice or something to the understanding of the problem or the resolution of the same ? other data as I can give. I have a Protoshield for arduino where I put the engines integrated, ground and VCC from the battery but there is continuity from GND to VCC, I did something wrong? or is normal to have that continuity

thanks for your time and i hope to solve the problem instead of buying another arduino, isnt cheap

the light become more tenuous and now sends me random numbers in the serial monitor trought analogRead,

That's a pretty amazing LED then, if it can do all that.

someone could give me some advice or something

I'd advise you to post your code.

but there is continuity from GND to VCC, I did something wrong?

I'd say yes, you did. Either you've created a short circuit, or you are measuring something incorrectly. Neither is a good thing.

thanks you for your reply.
this is the code i use to check the signal of the sensors

int sv = analogRead(A0);
int x = 250;
int v1 = 0;

void setup() {
Serial.begin(9600);
pinMode(sv, INPUT);
}
void loop() {
v1 = analogRead(sv);
Serial.println(v1);
delay(3000);
}

its just to monitor, i change the A0 pin number to chek pin per pin

another data its i brake up and patch a IDE cable (the old for hard disk) and was sending all the pins signal to all the pins so the arduino trough analogread was taking vcc and gnd for all the sensors
after that i notice that the LED on pin 13 was on i dont know perhaps 40% of brightness but i say its nothing perhaps im crazy.
but then the sensors show me random numbers and the sensor 1 was puting signals in all the analog inputs, i check continuity without nothing pin per pin and there's no continuity so i dont understand im a hobbiest everything i learn i learn for my self but more programming thatn electronics so that's why i dont understand

ttank you for your time