Got a digital camera?

Can you reach back far enough on the wires to get to the factory "bundle".....they should be taped together or inside of a cover. In that "bundle"/harness are all of the wires to and from the radio....in that bundle will be the YEL/RED wire....

In the pic you can see the factory plug (white rectangle) then the bundle of wires. If you can't get your hand in there you might have to remove the trim pieces around the radio to get back to the factory harness.

 

Word of warning first... I'm am starting to drink my coffee right now.

If the power (+) wiring is missing, there are options. You or someone can dig in there and try to find where the missing wire connected to, then you can connect another wire and either solder or use a crimp connector to splice the wires together. This may be difficult if not impossible to find the wire, without tearing out the whole harness.

The easiest option, is to just find another power source (+) which turns on when the ignition is on. An easy way is just to run an "Add-A-Circuit" fusible link from the driver's side under dash fuse box and extension wire to be the power wire.

Here's an example:

"http://www.amazon.com/Littelfuse-FHA200BP-ATO-Add-A-Circuit-Kit/dp/B0002BGELQ"

Btw: The fusible links are available at most auto parts stores, some Walmarts, etc.

 

You can add the fusible link to where the existing stereo fuse plugs in or pick another fuse location. On many Hondas, the diagram which shows "not used" can be use to add accessories. I would use tie-wraps to secure the new wire extension while routing it.