I'm getting mixed responses about joining the lcd monitor wires(Yellow,Black,Red) with the vehicle harness. I wanted to know if it would cause a fire or somethin. And also i'm trying to install a navigation box that uses the same wires, is there any specific area I should wiring the navigation box to?

At the top the yellows are put together.

 

Very little current runs though audio-video wires. The exception is power supply. Looks like you are using shrink wrap. Smart.

 

So I'm real confused where else am I suppose to get the power from other than radio harness?

 

^^ The radio harness will work for your project.

--Spike