Installing a third brake light

Installing a third brake light in a Porsche 944

I am not in any way associated with the Porsche Automobile Company
except for the fact that I own a car they built and like it.

What my car looks like with it installed.
(Notice the glow around the new light compared to the old ones... it is the brightest light on the car)

What it looks like thru the rear view mirror
Note: Never try to take pictures thru your rear view mirror while driving.

The parts kit (Note: The kit is Genuine Porsche Parts)

First, keep in mind, I am a software engineer, my helper for the project (my brother) is a electrical engineer. Neither of us are auto mechanics. We did not disconnect the battery before doing the installation although you may wish to.

These instructions come with no warranty implied or expressed, and as always, your mileage may vary.

Background:

It was a big hassle and took months before I got paid. Since all the aggravation of the last rear-ending, I've been trying to protect myself from getting hit again. (My brother says I'm psychologically scarred and I should sue... ;-)

One way I thought to protect my 944 was to add a third brake light. It's not required by law for a 1983 car, but with the low profile of the car, it just might save my behind someday.

Parts required:

Porsche third brake light assembly
Pelican Parts (PN# F-631-070-00) was $52.90 and is a Genuine Porsche part.
18 gauge wire (2 different colors)
A 3 spool (3 color) pack from Radio Shack (PN# 287-1226) was $4.49. The spools were just about the right length, we had little left over.
18 gauge wire quick connects
Radio Shack (PN# 640-3049) contains 8 connectors for $1.49 and they fit the Porsche light perfectly.
10mm socket and driver, or wrench
(This was the size of the ground lug near the spare tire on my 83 944)
Small Philips screwdriver
Cloth measuring tape or a nonstretchable rope.
(To measure center of hatch)
A small amount of Duct Tape

The kit:

The light kit consists of three pieces:
- a flange that mounts with double stick tape to the glass hatchback
- the light assembly itself
- 2 small Philips screws which holds the front of the light to the flange (the back interlocks).
Installing this is easiest done with 2 people, although one helper can roam in and out of the area at times and takes about an hour (unless you are inept like we are ;-), I think we spent 3 hours total, but we did other stuff too as we discovered new nooks and crannys in the car.

First, find where to position the light:

Tape the cloth measuring tape or non-stretchable rope across the back window. If using rope, trim each end so that rope exactly fits window. Remove tape or rope, fold in half and mark center. Put back on window so you can see marks from the inside. Tape some electical tape on the window to mark the center or put a few lines across so you'll have a visible line to see for centering the light.
Pop open your hatch. Climb in back-seat, and note space between hatch and light. Have your helper open and close the hatch. Determine where you can mount it and not have wires pinched when closed, yet have it high up enough that it is just about out of view in your rear view mirror. This is a judgment call.
Have your helper stand by the spoiler and open and close the hatch while you test fit the entire assembly
Once you determine where to place the flange, remove the orange protective strips from the tape, and stick in place. Have your helper visually check position from the back before you press into place.
With your helper placing a hand and gently pushing from the outside, gently but firmly press against the flange until you can see that the tape is firmly pressed against the window. DON'T PUSH YOUR WINDOW OUT!

Next step is getting power to to the light:

Gently remove carpet snaps covering tail light assembly on both sides.
Remove entire lower carpet section from trunk. We left it inside for most of the job then we realized "We're constantly moving this around..".
Locate ground lug between spare tire and drivers side turn signal assembly (this is where you'll be attaching your ground wire)
Locate black turn signal assembly on drivers side.
Remove white thumbscrew from drivers side turn signal assembly (this holds the cover on)
Carefully remove cover (light bulbs will come out with cover, use caution not to break or damage any)
Gently remove metal plate/bulb holder from black plastic cover (there are 3 plastic tabs that hold the two parts together). Pry them gently.
Just to be sure, have your helper tap on the brake so you know which bulb is correct. Then you tap on the brake while your helper watches so you both know the right bulb (saves arguments later).
P.S. It's the bulb closest to the spare tire.
Look at the back of your car, 2 wires must be run to the top of the hatchback. We chose to run 1 wire up each side thru the weatherstipping. The positive wire we ran up the drivers side as described below, the ground wire we ran up the passenger side as described below.

Positive Wire:

We ran the positive wire behind the drivers side wall carpet to the last opening in the side vents, then up into the hatch weather stripping. There, we pressed it under the weather stripping.
To get it past the hatch light, we first ran a fish wire down the 3rd vent opening until we could feel it in the fender flare well. The wire needs to be pulled out the 3rd vent hole and then worked over to the first hole.
Leaving at least 2 inches of spare wire, crimp quick connect lug at top of hatch. Wire will have to go through center of light, then bend at right angles to be in proper position for quick connects.
Place a small piece of duct tape inside vent on wire to prevent the wire from moving.

Ground Wire:

We chose to run the ground wire behind the passengers side wall carpet to the last opening in the side vents, then up into the hatch weather stripping. There, we pressed it under the weather stripping.
Remove the jack and run wire underneath to avoid snagging later. My car came with duct tape (factory installed ?) to keep the ground wires away from getting snagged by the jack.
Run a fish wire down the 3rd vent opening. The wire needs to be pulled out the 3rd vent hole and then worked over to the first hole.
Leaving at least 2 inches of spare wire, crimp quick connect lug at top of hatch.
Place a small piece of duct tape inside vent on wire to prevent the wire from moving.

Attachments:

Attach positive wire to lug on passengers side of 3rd light (You'll see that it touches the base of the bulb in the socket)
Attach ground wire to lug on drivers side of 3rd light.
Insert rear of light assembly into flange and use the two small phillips screws provided with light to secure front of light to flange.
Carefully loosen ground lug near spare tire. Your Radio Shack quick connect package came with 4 quick connects and 4 spade lug connecters. Attach one of the spade connectors to the wire and attach ground wire with the rest of the ground wires to the ground lug. Re-tighten using care not to over tighten or strip lug.
Taking care not to damage the wire, pull the quick connect terminal off the brake light on the drivers side tail light.
Here you have two choices:
- Carefully remove existing Porsche quick connect with pliers, twist (actually, my brother wanted to solder it, but it was a cold day and would have taken forever) old and new wire together and crimp one of the remaining quick connects from the Radioshack package onto the two wires. Reconnect.
- Insert new positive wire into one end of the existing quick connect and bend wire at other end of quick connect. Reconnect.
  Note: Realizing that the wire was old and might crack, we opted not to remove the quick connect and instead used the second option for attaching the wire. It was not our first choice, but we were concerned about breaking the wire and not having the length to reconnect it.

Finished:

Have your helper press on the brakes. Enjoy the glow....
Did it light up? Did you blow a fuse?
We installed mine over a year ago and have had no problems with fuses.
I can barely see the 3rd light in the rearview mirror. One thing I was afraid of was that I'd get a red glow at night on the glass, but with the light attached directly to the window, there is no reflection.
Mine is not perfectly straight, but very close... instead of asking my brother to stand outside the car, I should have looked myself... But it's not far off...
On my 1983 944 there have been no problems with the new light. The third brake light is the brightest light on the car and depending on the angle viewed at, is very large. A typical person driving a van or SUV would see a 6.5 inch long by 4 inch wide red light when you tap the brakes due to the angle of the light... Also, on Chicago streets even with the bright orange street lights, if I tap on my brakes, they will noticabley reflect off a bus stop sign two blocks away (1/4 mile). Pretty bright!

Want to yell at me over the above instructions? Email me at jwn@ripco.com