This 1997 Ford Mustang came in on a hook with a no crank condition, the starter would not work. I turned the key on and checked to make sure the dash lights came on. They did but as soon as I tried to crank the engine they went out. Seems like a battery cable connection. I opened the hood and this is what I found. I have mixed feelings about these painted temporary battery terminal ends. I hate them because they cause so much trouble. I love them because they cause so much trouble and I make my living fixing electrical troubles.
I thought I would show a trick of the trade for checking to see if a battery terminal is actually making contact with the battery post on a top post battery. Using a jumper cable clamp with a lot of tension hook one jaw on a clean metal piece of the terminal and hook the other jaw onto the top of the battery post and make sure it digs in real good. If the vehicle now has enough power to start the terminal, the post or both are corroded or oxidized enough to prevent power from flowing. Keep in mind that this can be dangerous. A poor connection can create an arc, a battery produces hydrogen gas and together they cause an explosion that can spray battery acid.
A safer way is to use a voltmeter and do a voltage drop test. Starting at the battery posts and working out to see if the voltage changes.
The positive cable connection was the problem. I think you can see the oxidation in the following picture. The battery post and the terminal were both heavily oxidized
You can also see corrosion under the clamp.
I cleaned the cable back to clean copper and stripped off some insulation, about 3/4″.
I placed a ring terminal over the exposed copper wire and crimped it in place.
I repeated this with the ground cable and soldered both assemblies. Notice I removed the battery. Open flames and hydrogen gas are not a good combination.
I used a butane torch to heat the connection up enough to solder it together.
Then I installed some heat shrink tubing.
I used a heat gun to shrink the tubing and seal the connection.
Repeated on the negative cable assembly.
Installed the ring or eye terminals onto quality marine type battery terminals.
I also installed a protective boot onto the positive cable assembly.