Wiring diagram design app

Does anyone here know of a good app or program to design professional diagrams?

I want to be able to have a diagram I can include in my documentation. Thanks

I use OpenOffice Draw. Build up a library of connectors you use, and it can make a pretty good diagram. Here is an example of one of mine.

Thanks!! I’ll give it a try!

I do a netlist in excel and a harness diagram in visio similar to David. I then use cells to the right to calculate wire lengths (excess(4") + additional for twisting(20%) etc)

This is all you really need. The next thing which helps a LOT with fixing things, reverse engineering (aka.. original person gets hit by a bus, etc) is an actual wiring diagram. Visio does this well as well.

Ok awesome!