'93 with 4.3 W engine
My dashboard battery gauge has been jumping around erratically and red lining so I just replaced both battery cables as the first step to fix that. Hoping to not need new alternator or battery. Here's where the issue starts: all wires replaced in the same way except that originally nothing was attached to the auxiliary on positive cable so I attached the non-alternator wire there. When I went to reattach the cables to the battery it arcs big-time and the starter turns over. This is without keys in the ignition, I'm not that dumb but I do want to say: I'm a Chef NOT a mechanic although I'm trying! What did I do wrong?

 

You didn't happen to pinch the solenoid wire under the main positive battery cable at the starter did you?

 

The starter could be bad. There is a solenoid in the starter that moves the contacts "on and off". The contacts could be burnt together in the start position on the starter itself. You could try to take a hammer and knock it back loose. Youd go by tapping the starter with the hammer a few times and then try to hook up the battery cable after each time. If it doesn't try to start on its own you'd then of aceived victory.

The starter shouldn't be "laid on". That is what would make the contacts burn together. Never crank for longer then a second or 2 past "normal".

The arc is from the high amp demand coming from the power hungry starter being stuck on.

 

I would check to see if when you pulled more slack to put on your cables you may have touched your purple wire on the starter to the main feed to your battery Just a guess