DON'T LEAVE THE KEYS IN THE VEHICLE IGNITION IN THE ON POSITION. Why? Because the battery will be dead in a few hours. That happened to us yesterday. We noticed the lights were on, then tried to start it. Click. Again. Click. It was 5 pm, so we decided to wait till this morning to address the problem.
Around 11, we called AAA. Guy arrived in less than 30 minutes. After jump-starting the truck, he returned to his shop for a second battery. We were only vaguely aware that a diesel truck needs 2 batteries to get started. Soon, he returned and started the installation.
He removed numerous bolts and took out one battery.
He used that battery as a step to make it easier to install the new battery.
After repeating the process for the second battery, he tested both to be sure they were putting out the correct voltage and to make sure there was no short circuit somewhere, draining the batteries. He was able to print out these reports for us.
In less than two hours after placing the call to AAA, and after a hit on our credit card for over $300, we were back in business, able to drive our truck again. It was really very simple, if a little pricey.
You better believe, we won't do that again. (Cross our fingers.)