Why Disconnect the Negative Battery Terminal First
When disconnecting the battery in my truck, the Haynes manual says disconnect the negative battery terminal (first). I recall the install instructions for the radio I bought for the Miata last year said the same thing.

Why? I have asked myself that question several times but I never think to Google it while I am at the computer. Well today I remembered.

If you disconnect the positive terminal first and you wrench happens to contact any part of the car that is grounded, you will have a short between the positive and negative terminals. (Shorting the battery could burn up some electronics or cause the battery to explode!) That makes perfect sense. I can't believe I didn't figure it out myself.

I am pleased to announce that I did not have to learn this lesson the hard way.