Please help me find a grommet that will...

I'm installing a 3rd brake light (LED strip) on the louvers of my '82 ZX (an interior one wouldn't be visible).

I need to run wires to it through the metal at the top of the hatch (I'll drill a hole).  To do this, I need a grommet that will be tough and waterproof.  I don't care if it is a little odd looking--I want the safety of the 3rd brake light.  I've looked at auto stores, home centers, etc. etc.  I can't find anything.

Can anyone tell me what I could use and where I could get it? 

(It has to be weatherproof and tight.  If water gets in, it will ruin the entire hatch.)

Thanks for any advice!  This project has been on hold forever.

You can probably go down to your local autosuond shop and get what I used to use. It's called "strip caulking". Its a black kinda sticky caulk that comes in 1/4" strips that you can mold around the wire before you pull it through the hole. (God, this sounds sick!)

Pull you wire through the whole until you get to the last six inches, stop, wrap the caulk around the wire, like a doughnut, then in a tight spiral around the wire, taper the caulking up the wire about 2". Finish pulling the wire through the while pressing the caulk around the hole as it feeds through. This will allow a tight, waterproof and flexible seal, (is not near as messy as using silicon, which you could use as an alternative). This is the method I use religiously with drilled firewall and door jamb holes. I would also use this in combination with rubber grommets. Only takes a few seconds to apply it and pull........

But it just occurred to me that all this might be visible. If it is, then go with the silicon and use a piece of 1/4" wire loom (the black plastic flexible stuff that slips over wiring harnesses to cover them up.

NOTE - This thread was restarted later at: https://www.the12volt.com/installbay/display_topic_threads.asp?ForumID=1&TopicID=6733&PagePosition=1#thread