I honestly have no Idea what has happened to my hummer h3 today.
I was looking to replace the factory radio, successfully removed it but during the removal process the car seemed to go completely dead,the key was in the ignition but got locked in and the gear shifter siezed. went ahead and bought a new radio but something seemed wrong so put in the factory radio and the car is completely unresponsive. Horn doesn't work, can't change gears, key is stuck in ignition, no sign of power anywhere. Tried clicking key fob and nothing is responding. I have tried reconnecting battery but no luck. Have no clue as to whats wrong.
It's a 07 hummer H3

 

Look for thread about body control module. Reset think it's 7 mins off then10 seconds ignition on no crank three times. It's that alarm feature 110 years of GM engineering and they still suck like hovers lol. Find someone with tech 2 to reset radio connection you can see what radio your running Thu computer it's crazy is lock symbol flashing on dash?. The passlock is what it's called. 7 min off 10 seconds ignition on three times to reset. Good luck.

 

No the lock symbol isn't flashing, its acting like there's no battery in the car, but I'll try what you suggested

 

There is a solenoid that locks your key in the ignition if you lose battery power. Double check your battery connections and make sure you did not blow any fuses. When you said the car died while replacing the radio; makes it sound like you did not disconnect the battery before starting. Always disconnect the battery before unplugging or unwiring anything in the car (even the radio). You may have grounded out a hot lead and popped a fuse. If you have the I5 motor, the fuse box is in front of the battery on the drivers side.

Good luck.

 

Check your battery connections have someone jump your battery also. Might be one of those square plug in fuses in fuse box under hood. Logic probe helps can just touch the spot provided on top of fuses for checking. Finish the work on the radio per the instructions hate to find the fuse only to blow it twice. If you find fuse blown and it burns again maybe your radio is miswired also. Inline fuses at radio can save you getting stuck if something goes wrong better to blow these than the one running your car. Tap the black Relay squares in the fuse box with screwdriver handle lightly if power comes back on even briefly it's a bad Relay. Six of the Relay are same so you can swap them around see if anything changes. Might be crappy battery cables clean them good then tighten. Your going to find it don't stress.🙄

 

You blew a fuse. Check #5 & #33, it's possible that you could have killed the megafuse #91

 

or you need to replace your battery connectors if they are the original ones. I'm surprised you didn't mention that Hummerz... lol.

 

I have over 30yrs (as a master tech and service manager) of experience!...

Read the post again, and explain how the battery terminals could fail during a radio replacement?

Lost all power during removal process:

 

at the point he lost all power.... if its not fuses then its battery connections.
you know how flakey those battery terminals can be. how do we know he did not touch anything near there or breath on it lol.maybe there was an after market amp involved at some point.

 

Same modus operandi my Toyota Sierra went cold dead could not even be jumped. The battery connectors had weird filament built in that rusted through and stopped power from leaving battery moved a cable hard and the connection sparked looking close I realised what was happening. Had to cut off both connections and use bronze boat connecrors. Then all was well.😌