In Canada, all vehicles manufactured at 1987 model years or later have to have a 3rd (upper, center) brake light in order to be registered. My 94 S4 V8 avant never had one from the factory because it went from Germany to Japan in 1994 and never left until it was sold to a Canadian (not me) in 2010. When the car reached Canada, someone added a very sketchy third breaklight with some tiny LED stick on strips. It always caused a "Brems Licht" warning in the autocheck and the wiring was also very sketchy. I fixed the wiring but but I hated the sketchiness of the install. As a result, I have been trying to figure out a solution using VAG parts (VW Golf, Jetta, maybe Passat and Audi). The latest attempt involves a C4 sedan third brake light that came from the factory with ten 2.3W bulbs. I will have to relay this off the left rear taillight using the trailer connection tab on the lamp holder.
One of the issues is this all has to fit inside of the very tinted (OE "crome vaporized" (or chrome smoked)) glass on the non-spoiler hatch of the 94 V8 S4 avant.
This post looks at the latest iteration of this "game", possibly using an OE UrS4/S6 sedan third brake light assembly that would be screwed to the upper middle hatch trim strip (which snaps into OE holes in the hatch).
I had visited a LED shop last week and but didn't have the OE UrS4/S6 brake light assembly with me. Yesterday I went back with the strip. I told them what I wanted and in about 10 minutes and $12.16 later, I was out the door with a 15 LED light strip temporarily installed behind the OE red lens. They suggested that the 15 LEDs were the equivalent of 30W (??). (Seems low)
The following steps everything back and shows the process.
This is the OE C4 sedan 3rd brake light assembly (in this example, from a 95 UrS6). The assembly is clipped to two brackets that are bonded to the rear glass. The assembly will come off and, to do the LED conversion as will be shown here, it would have to come off to access the front lens area.
The OE third brake light assembly can be broken down into its components:
This photo shows the 15 LED light strip (stuck to an aluminum bar to keep everything nice and straight) about to be installed into the OE third brake light base
But first, I better show the comparison between the 10, 2.3W OE light strip (outside of the assembly) and the 15 LED light strip, both powered by the same 12V supply.
The photo actually makes the OE bulbs look brighter than they were. In reality, they looked very dull compared to the LEDs.
I only had these lights on for a few minutes while I took the photo. I had to check the LEDs for heat, so I touched them. Cool. Then, not thinking, I touched an OE bulb. OOOWWWWch. Fugg! Darn near burned myself. Yikes. Okay, LEDs win the heat issue.
Okay, back to the plot: here is the 15 LED light strip installed behind the OE red lens. For my application for the avant, I need the wires to go out the back (in a normal sedan application, you'd run the wires out the front in the little OE wire channel). I initially drilled a small hole beside the left most chrome reflector and ran the wires out there. Worked sort of but the light strip didn't sit in the assembly 100% so I disassembled and ran the wires out through the empty bulb hole in the left most OE reflector.
Here is a close up of the LED strip behind the OE red lens.
Okay, now the results. I waited until dusk to do this. Unfortunately, I didn't have two assemblies so I had to trial one at a time. I can't even remember which one got trialled first. I don't know if the results shown in the composite photo below are representative of both or not. It does show that the OE reflectors do tend to multiply the visual impact of those 2.3W bulbs by a large factor. I am going to carry on with the LEDs if only because once installed, I shouldn't have to go back and change the LED strip for a long time.
YMMV
BTW, this would probably be a slam dunk with the OE hatch 3rd brake light with its easier access to the bulb holder. Not sure if the lack of resistance would trigger at check bulb warning on the autocheck if the vehicle was originally equipped with third brake light.
One of the issues is this all has to fit inside of the very tinted (OE "crome vaporized" (or chrome smoked)) glass on the non-spoiler hatch of the 94 V8 S4 avant.
This post looks at the latest iteration of this "game", possibly using an OE UrS4/S6 sedan third brake light assembly that would be screwed to the upper middle hatch trim strip (which snaps into OE holes in the hatch).
I had visited a LED shop last week and but didn't have the OE UrS4/S6 brake light assembly with me. Yesterday I went back with the strip. I told them what I wanted and in about 10 minutes and $12.16 later, I was out the door with a 15 LED light strip temporarily installed behind the OE red lens. They suggested that the 15 LEDs were the equivalent of 30W (??). (Seems low)
The following steps everything back and shows the process.
This is the OE C4 sedan 3rd brake light assembly (in this example, from a 95 UrS6). The assembly is clipped to two brackets that are bonded to the rear glass. The assembly will come off and, to do the LED conversion as will be shown here, it would have to come off to access the front lens area.
The OE third brake light assembly can be broken down into its components:
This photo shows the 15 LED light strip (stuck to an aluminum bar to keep everything nice and straight) about to be installed into the OE third brake light base
But first, I better show the comparison between the 10, 2.3W OE light strip (outside of the assembly) and the 15 LED light strip, both powered by the same 12V supply.
The photo actually makes the OE bulbs look brighter than they were. In reality, they looked very dull compared to the LEDs.
I only had these lights on for a few minutes while I took the photo. I had to check the LEDs for heat, so I touched them. Cool. Then, not thinking, I touched an OE bulb. OOOWWWWch. Fugg! Darn near burned myself. Yikes. Okay, LEDs win the heat issue.
Okay, back to the plot: here is the 15 LED light strip installed behind the OE red lens. For my application for the avant, I need the wires to go out the back (in a normal sedan application, you'd run the wires out the front in the little OE wire channel). I initially drilled a small hole beside the left most chrome reflector and ran the wires out there. Worked sort of but the light strip didn't sit in the assembly 100% so I disassembled and ran the wires out through the empty bulb hole in the left most OE reflector.
Here is a close up of the LED strip behind the OE red lens.
Okay, now the results. I waited until dusk to do this. Unfortunately, I didn't have two assemblies so I had to trial one at a time. I can't even remember which one got trialled first. I don't know if the results shown in the composite photo below are representative of both or not. It does show that the OE reflectors do tend to multiply the visual impact of those 2.3W bulbs by a large factor. I am going to carry on with the LEDs if only because once installed, I shouldn't have to go back and change the LED strip for a long time.
YMMV
BTW, this would probably be a slam dunk with the OE hatch 3rd brake light with its easier access to the bulb holder. Not sure if the lack of resistance would trigger at check bulb warning on the autocheck if the vehicle was originally equipped with third brake light.
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