Wiring question for third brake light...
 

Well, for the second time in the past week, I've come thisssssss close to being rear-ended by a tail-gating SUV POS. I've bought a third brake light (22 LEDs, very bright) to install on my car. I've read previous posts about people installing them, but there's no real details about how to run the wires, etc. Here's what I'm looking for and I'm hoping some Pelican heads can provide:

1) what's the best way to tap into the left break light from inside the cabin. I'm sure I have to drill a hole to run the wire, but I'm not sure what color the brake light wire is, and where it is. Do I just need to get the wire into the engine compartment?

2) since I have a targa (check sig), what's the best way to run the wire inside the cabin to conseal it?

I've asked a couple of the peeps who've posted about third brake lights about this, but I have not gotten a responsce yet. If someone can get me started, I'll post a step-by-step myself with pics, helpin out any other pelican head brothers :)

Help get me started guys. BTW, any pictures would be great!

If I were lazy (Really, I am) I would just route the wire from the window, below the rear deck, side panels, and carpet. Through the center tunnel and all the way to either side of car and hook it straight up with existing brake lights.

Or I would drill a hole to the rear deck, put a wire through it and seal the hole, and then attach the wires in parallel to rear brake light wires.

I'm sure I'll have to drill a hole either on the rear, side wall towards the engine compartment, or through the shelf above the engine. But I'm not sure exactly where to hook into the existing braking system wiring. I could probably spend an hour tracking down the wiring, but I thought somebody might just know.

Ah, yea..read your post so fast that I did not see that you needed the colours...Have you checked the electrical diagrams on the website?

http://www.pelicanparts.com/911/911_Parts/911_electrical_diagrams.htm

Here's what I did:

1) At the bottom of the window (on the drivers side) under the "package shelf" (after removing), there was a small hole in the very corner between the rear and side quarter glass which drops to the engine compartment.... no drilling required!

2) I mounted my light at the top of the rear window. The wires fit nicely tucked behind the rubber lip of the window seal, ran both (hot and ground) all the way down behind the lip, can't even tell it's there. This drops the wire right to the hole described above.

HTH.

Sounds pretty simple. How did you know which wire was the brake wire inside the engine compartment?

The Haynes manual has the color codes for the wires on the electrical diagrams (should be black w/ yellow stripe), once I found the wire, I tested (double-check!) with a volt meter and splice it in. The ground went to the common ground point on the driver's side of the engine bay.

HTH.

Thanks, that helps alot. Is the wire easily accessible from inside the engine compartment?

Matt,

From the following diagram ... looks like the wire is Black/Green after connector 'T2f' right up to the junction at the right-hand 6-pole body thru-connector to the tail-lamp assembly, then Black/Yellow over to the left 6-pole connector and on to brake lamp sockets.

http://www.pelicanparts.com/911/911_...SC_Part3-1.jpg

Not sure if it's the same on the SC's, but on mine it wasn't terribly hard. The only minor obstacle was that I had to remove the fuse/relay box in engine compartment (on driver's side) as the wire bundle is routed behind it. Other than that it's easy.

Definitely a DIY project.

There is no rear/quarter window in a Targa, it is one piece of glass. What hole are you referring to?

Anyone looking for third-light setups should visit an RV accessories shop.

John

Mine's a coupe, so probably different... Targa's may not have it. The hole is about 1/4" in diameter, was under the sound padding. Definitely factory, as it was painted with smooth edges.

Matt,

Hope you are mounting it high, better for all those big Awowa SUVs to see you!

This link may help.... http://forums.pelicanparts.com/showthread.php?s=&threadid=97229&highlight=third+b rake+light

Matt--
RickM's link is a good one (it was my thread to begin with). I just completed this a couple of weeks ago and it was definitely pretty easy. My thanks to all who provided opinions and help.

There is definitely a hole (at least there is on my '85 Targa) at the rear of the window (driver's side) into the engine compartment. The rear window defogger wires run through it. If you open the engine compartment you can see them coming down.

I GENTLY ran a coat hanger from the engine compartment up through the hole into the passenger compartment, attached my hot and ground wires and GENTLY pulled them into the engine compartment. I used 18 gauge wire, since the original third brake lamp wiring was even smaller than than when I looked at another unit.

I found a ground behind my fuel filter, so I removed the clamp holding the fuel filter to better get access to it. I crimped a ring connector the ground and attached it there.

As for the hot, the wiring diagram for my '85 showed the taillights to be black/yellow like Superman describes.

I removed the cover of the rear fuse box, again to get better access, but didn't have to remove the fuse box itself. Its very easy to route the new wire under the fuse box and toward the rear taillight. Pull the 6 pin plug out of its socket by the rear taillight and undo about 6 inches of the black tape to gain access to the wire bundle. You should find the black/yellow wire there.

I tapped into the black/yellow using the connector that RickM posted, though I ended up using the smaller red 18/22 gauge connector, rather than the blue one he shows. Both the existing black/yellow and the new wiring I was running were too small for the blue connector. The connectors are available at Radio Shack and Home Depot.

Once you've done your connections, I'd suggest that you test before closing it all up and mounting the light itself (I did that last). The ignition switch must be ON for the brake lights to work - my first test was with the ignition off; I pushed the brake pedal and nothing (minor panic). Ignition switch ON, and I had light.

I sealed the red connector with liquid electrical goop and then re-wrapped the wire bundle with electrical tape. Then used wire ties to make everything neat.

Took me about an hour total, including a trip to the hardware store for the liquid electrical tape.

I was planning on taking pictures, but didn't have batteries in the digital camera. Maybe I'll take some and post later to show the finished installation.

Hope this helps.

Nice description Steve. I probably used the red connectors on my installation as well.

The blue example I utilized was for educational purposes only. :p

And a great example it was - since I had never heard of or used them, I was able to walk into Radio Shack and say "I need one of these" - sales guy walked me right over to where they were and asked "what size do you need, sir?"

thanks again for the help.

Well, my third brake light kit has a connector already, so I'm set there. When you're talking about the "connector", is it that round connector which seems to plug into the driver's rear wheel well from inside the engine compartment? If that's it, it's REAL easy to get to. And that would mean that the blk/yel (usually means a black wire with yellow stripe) would be the wire "inside" the engine compartment. Zat right?

Matt,
My light didn't come with any wiring at all. However, The connector we're speaking of is a "Wire Tap connector" as shown in the link I supplied earlier (did you look at it?). You must tap the new wire into the existing black wire with yellow stripe using the red connector (which you buy from RS or HD). The existing wire is bundled in the harness behind the tail light. I believe Steve described pretty well. I am not aware of any existing connector in an SC for this purpose.

Perhaps the connector you have is designed for a newer 911 that has the proper factory accomodations for a 3rd light.

Matt-
yes, the 6 pin plug (I corrected it in earlier post for clarity) is the one I was talking about and yes and yes to your other points.