GoogleApiClient - Unable to start service

Question

I'm trying to make a the LocationUpdate as a service (from the Play Services v7) and I have this error:

Unable to start service com.package.etcetc... GoogleApiClient is not connected yet.

This is my android Manifest:

...
<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">
    <meta-data
        android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <service
        android:name=".LocationService"
        android:enabled="true" />
</application>
...

MainActivity calls the service:

startService(new Intent(MainActivity.this, LocationService.class));

And here is my full java code: http://pastebin.com/hgjKKmMr

Any advices?