Cant change android action bar back button icon

Here is the situation where i stucked with i cant change my action bar back button. Tried many ways but still displays the default icon. Any help will be appreciated.

Style.xml

        <resources xmlns:android="http://schemas.android.com/apk/res/android">

<!--
    Base application theme, dependent on API level. This theme is replaced
    by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
-->

<style name="AppBaseTheme" parent="android:Theme.Light">
    <!--
        Theme customizations available in newer API levels can go in
        res/values-vXX/styles.xml, while customizations related to
        backward-compatibility can go here.
    -->

</style>

@style/MyActionBar

<style name="MyTheme" parent="@android:style/Theme.Holo">
     <item name="android:actionBarStyle">@style/MyActionBar</item>

#252525
@drawable/bg_line
@style/MyActionBarTitleText

parent="@android:style/TextAppearance.Holo.Widget.ActionBar.Title">
@color/textclr_actnbar

— modified on Dec 5, 2014, 8:00:48 AM