I'm replacing the OEM radio with a Pioneer CD player type. I discovered that the Pioneer mounting rack will slip into the mount that's held on to the OEM radio with 4 screws. I slipped it in place, and made some solder joints to hold them together.
Good part is, when the dash trim was put on for a look, the radio fit perfect & looks like it belongs in there.

But.....the color code of the wiring to the OEM radio connector doesn't match the electrical diagram in the Factory Service manual, so I had to use the ohm meter to probe the wires, and the meter will make speaker noise when the correct wires are located.
And, the antenna connector in the right side kick panel fell apart, so I had to replace the female part. It wont fail now...I soldered the two together..

Bottom line is, the factory wiring diagram for the radio sucks big time..

 

That's why you get the wiring harness converter and blammo wire it up faster than you can say pewpty poopy pants. Also no cutting the factory harness which can cause issues.

 

What he said, plus when you wire the adapter use shrink wrap, solder and heat (hair dryer will do) and it is as easy and clean as can be!

 

I didn't want the adapter. I wanted to keep the connector for the old radio, so the radio could be used for something else. The Pioneer had a pigtail & connector with it, so I matched the connections with the Jeep radio harness.
I do avionics in airplanes yet, so wiring a car radio isn't difficult, specially if the wires are color coded right. Some of these wire were OK, most were not. And I do use soldered connections & shrink tubing....

Anyway, I finished it today, and it sounds great. The Jeep has better speakers than I thought it did.!!
And the wife is happy, and you all know what that means She claimed it early on, and the Park Avenue just sits !