Hi. Im trying my hardest as of late to do more hands on work on a 70 chevelle,with a bb. Can someone give me a clue as to how to read wiring diagrams, from a manual,in regards to identify a specific wire,what its for,where it goes.. I know some,but say I find a wire under the dash that has a plug connection with several wires,, how can I identify where its suppose to go.. I have been trying,and making some progress,with cleaning up all the garbage that the previos owner did.. Another example that comes to mind is a wire on the pass. side of the engine from the firewall that goes to the motor down under....... its not for the starter or the heater. Now understand that most of the wiring in the engine bay are painted over.. so colors mean nothing.... I reread this post and I think I will end up having to go back to school.. Any tricks or insight will be appreciated.....phil

Paint on the wires isn't a good thing, it makes it pretty hard to ID the wire. Your might want to lightly scrape some of the paint off the wire so you can see what color it is. Wiring diagrams will have an abreviation for the color of the wire. You can also get a good idea where the wire goes based on the length of the wire. The wire that you see going over to the passenger fender is orange and it powers the heater blower. Sometimes when I'm having trouble tracing done where a wire goes on the diagram I will use a highlighter to help me keep track of where it goes. One other thing to keep in mind is that wire diagrams usually start at the front of the car and work to the back. Watching where the major connectors are will help isolate whether the harness is in the engine bay or the dash harness etc.. Good luck, be patient and think of diagram as a road map.

Sometimes when I'm having trouble tracing done where a wire goes on the diagram I will use a highlighter to help me keep track of where it goes.

It's also, imo, a good idea to get a roll of masking tape (cheap) or electrical labels (more expensive) and mark the wires themselves, as you trace them. Mark them with a label at start and end points, as well as strategic locations between.

Thank you both for the hints, It makes good sense too.. I especially like the idea of labeling,and cleaning up the wires to see the colors.. phil