How do you replace a block heater on a 2008 GMC sierra 1500?

To replace the block heater on a 2008 GMC Sierra 1500, first disconnect the negative battery terminal for safety. Then, locate the block heater plug, typically found near the engine block, and remove the old heater by unscrewing it with a socket wrench. Install the new block heater by screwing it into place and reconnect the wiring. Finally, reconnect the battery terminal and check for leaks or proper function before starting the engine.