Battery issue

I just replaced the positive and negative cables to my 1999 Jetta and am not able to turn the vehicle on. Upon opening the doors the interior lights do not come on, the map lights are extremely dim, and when I turn the key to run the clock resets. There is also not enough power for the door locks, windows, or side mirrors to operate. You can hear the individual motors try to engage but the power is not enough. I tried to jump start it but that failed as well.

Sounds like your battery is dead. Or you have a really poor connection on one of the cables, although the positive side goes through the fuse link box for all the car side stuff. The big cable is just for the starter.

I am getting between 11.5 and 12.2 volts on the battery, starter, and upper battery box cables.

What about voltage drop from the negative side of the battery to the body?

I have not seen any, but I will test that again.

Why were you replacing the battery cables in the first place?

-J

The cables themselves had damage that was exposing the wire with excess fray in the middle of both the positive and negative cable. I was not able to do a crank voltage drop test, but when I was testing the headlights the same drop in voltage cause all systems to not receive any power. When I turned the headlights off then I was able to see the clock and hear the motors attempt to engage.

Turn the key on measure the battery voltage -on both posts-, then on both terminals.
12.6 should be a fully charged battery, 11.5 to low.
With the lights and key on measure the voltage from the battery negative post (not the clamp) to the body metal somewhere under the battery. I would not want to see more then a few tenths of a volt.
Next from the battery positive post to the power feed in the fuse box over the battery, and on the connectors leaving that fuse box. Same few tenths.
Sounds like a bad or dead battery from your voltage readings if you measured it at the battery posts.