constant power, 86 pontiac grand prix

I got a 86 pontiac gp that had a really really ridiculously old AM only radio in it. I for the life of me cannot find the constant power wire. I've identified the switched wire just fine but Im begining to suspect that there may not be an exsisting constant power wire going to the old stock harness. Any feed back or suggestions would be greatly appreciated.  

The constant wire is generally only for memory.  I suspect yours doesn't have one.

 Right, but im trying to put in a newer head unit that requires constant power. Sorry I should have mentioned that before.

Which means you'll probably have to find a new constant at the fusebox.

 OK well I think the biggest problem right now is that im a newb. So perhaps you can give me some more detailed instructions

Get yourself a test light & check the cig lighter for constant power.  Or a multi-tester & find a wire behind the fusebox that's constant.  Tap in & run to new headunit.  Be sure to verify that the constant power needs of the new HU are very low, like less than 1 amp.  If larger then you have a different problem.

At the ignition harness under the dash, you will have a thick red wire.  This is constant power.  Connect a fuse holder to this and run a wire from this to your deck.  Use a 5 to 10 amp fuse.  It's always wise to test all wires with a multimeter for proper function.  You can pick up a simple one at RadioShack for around $20.My ex once told me I have a perfect face for radio.