Component interaction via service not working in Angular2

I'm trying to set a value in one component, if a function is triggered in another component. However, I can not get it to work. I am using the approach given in this post

I would like my Sidebar to only show up after the Login-Button was pressed.

I wrote a service component like this:
component-interaction.service.ts

import { EventEmitter, Output } from '@angular/core';
import { Injectable } from '@angular/core';

@Injectable()
export class ComponentInteractionService {

        showSidebarEmitter: EventEmitter<any> = new EventEmitter();

        setSidebar(showSidebar:boolean){
            this.showSidebarEmitter.emit(showSidebar);
        }

}

and then I subscribe the components that would recieve the new values like this in my sidebar.component.ts:

import { Component, OnInit } from '@angular/core';
import { Router } from '@angular/router';
import { ComponentInteractionService } from '../services/component-interaction.service';

@Component({
  moduleId: module.id,
  selector: 'app-sidebar',
  templateUrl: 'sidebar.component.html',

  styleUrls: ['sidebar.component.css'],
   providers: [ ComponentInteractionService ]
})

export class SidebarComponent implements OnInit {
  showSidebar: boolean = false;

  constructor(private _router: Router,  private _componentInteractionService: ComponentInteractionService) { }

  ngOnInit() {
      this._componentInteractionService.showSidebarEmitter.subscribe(res =>this.showSidebar = res);

  }

}

and I'm setting the value in my login.component.ts like this:

import { Component, OnInit, EventEmitter, Output } from '@angular/core';
import { Observable } from 'rxjs/Rx'; 
import { ComponentInteractionService } from '../services/component-interaction.service';

@Component({  
  moduleId: module.id,
  selector: 'app-login',
  templateUrl: 'login.component.html',
  styleUrls: ['login.component.css'],
  providers: [ ComponentInteractionService ]
})
export class LoginComponent implements OnInit {

  login(){
   this._componentInteractionService.setSidebar(true);
  }
}

now, since the value in my sidebar.component.ts is subscribed to the emit event it should be updated as soon as it is changed, should it not?

Thank you for your help :)