Pass value from several objects into one JS

Hello.

I am struggling with something here and i got little bit confused.

I want to pass (continously) a value from several different objects into one. Let's say, that i'm making side scrolling game and i have 2 buttons for running left and right. My player have a variable "inputHorizontal", which depending of it's value (1 or -1) will make the player run left / right.

Now i have to pass 1 from one of the buttons and -1 from the other into that same variable "inputHorizontal" and in the same time if i press one button and release it, inputHorizontal, shoud go back to 0. For some reason only one of the buttons work and pass value to the variable and only if i deactivate it, the other one starts working.

For the purpose i've made simple scripts, so i don't need to copy tons of code here. Here's the 2 buttons scripts, which are identical except the value passes 1 or -1.

Script name : MoveButtonLeft_JS

 #pragma strict
 
 // Public Variables
 public var inputHorizontal    : float;
 
 // Private Variables
 private var printValue        : z_PrintValue;
 private var onPress            : boolean;
 
 function Awake()
 {
     printValue = GameObject.FindGameObjectWithTag("GameController").GetComponent(z_PrintValue);
 }
 
 function Update()
 {
     printValue.inputHorizontal = inputHorizontal;
     if (onPress)
         inputHorizontal = 1;
     else
         inputHorizontal = 0;
 }
 
 function OnMouseDown()
 {
     onPress = true;
 }
 
 function OnMouseUp()
 {
     onPress = false;
 }

Here's the second button script Script Name: MoveButtonRight_JS

 #pragma strict
     
     // Public Variables
     public var inputHorizontal    : float;
     
     // Private Variables
     private var printValue        : z_PrintValue;
     private var onPress            : boolean;
     
     function Awake()
     {
         printValue = GameObject.FindGameObjectWithTag("GameController").GetComponent(z_PrintValue);
     }
     
     function Update()
     {
         printValue.inputHorizontal = inputHorizontal;
         if (onPress)
             inputHorizontal = -1;
         else
             inputHorizontal = 0;
     }
     
     function OnMouseDown()
     {
         onPress = true;
     }
     
     function OnMouseUp()
     {
         onPress = false;
     }

and this is the script, that, the above 2 buttons shoud feed the value to. This script is attached to game object, that is tagget as "GameController": Script Name: z_PrintValue

 public var inputHorizontal    : float;
 
 
 
 function Update()
 {
     print (inputHorizontal);
 }

Why only one o of the scripts is passing information and the other one doesn't :\

thanks :)

inputHorizontal