Take a glow plug and connect it to the ignitor and see if the glow plug "glows". If your glow ignitor is new, most manufactures recommend charging it for 16 hours on a wall wart charger before first use (the charger that came with it). If your ignitor is old, then you might have a bad battery which they are usually replaceable.
When you are charging the ignitor you will know when it is ready/charged when the ignitor feels a little warm.
Hope that helps,
Mike