1997 Hummer H1 Glow plug

When I turn the key in my hummer normally there is a soung glow plug I think warming up the wait light flashes then you crank, now when I turn key no sound wait light flashes twice. It will crank fine but there always been a sound. Battery was dead so I put a trickle charge on battery for 24 hours battery is charged but mybe a blew a fuse for glow plug I live in florida so its not cold. I dont drive it much but there always been a humm sound when I turn key first notch wait for glow plug light to go of and sound stop then I crank. Any suggestion would be great help Thanks