Truck 3rd Brake Light - Done! and with Piccy Goodness...
Posted: Sat Apr 09, 2005 4:16 pm
Kind of off topic, but I figure someone here might be able to lend their expertise to my conundrum.
As pictured here:
http://www.akardam.net/temp/3rdlight.jpg
The shell I have on my truck has the 3rd brake light handing down in the back window. This is precisely where I wish to place my nifty-rific traffic advisor. So, what I thought, is I could get a simple red no-smarts surface mount LED lighthead to place on the back of the shell above the rear window.
Caveats:
1. The current factory solution uses two bulbs and is fused with a 5w ATO fuse. Any replacement should fall within those power specs (so I can use the existing wiring).
2. As you can see from the pic, while on the outside there's this nice flat space to work with, on the inside there's part of the framing that runs right up the middle. Thus, whatever solution I chose (whether one long lighthead or two smaller lightheads side by side) need to be able to put mounting and power not through the center (I really don't want to drill through that rib there).
3. The back of the shell tips forward. It's not much, no more than a couple degrees, so unless I wanted to make some sort of bevel to install the lighthead in a perfectly vertical alignment, whatever solution I choose would have to have a wide enough off-axis light level to be usable and safe. A bit of digging around located the following information:
From CVC 24603 http://www.dmv.ca.gov/pubs/vctop/d12/vc24603.htm :
"(h) Any supplemental stoplamp installed after January 1, 1987, shall comply with Federal Motor Vehicle Safety Standard No. 108 (49 C.F.R. 571.108)."
From 49CFR571.108 S5.1.1.27 http://squid.law.cornell.edu/cgi-bin/ge ... &TYPE=TEXT :
""1) Shall have an effective projected luminous lens area not less than 2903 square mm. (4 & 1/2 square inches)." and "(2) Shall meet the visibility requirements specified in S5.3.2(c)."
From 49CFR571.108 S5.3.2(c):
"(c) A high mounted stop lamp must have a signal visible to the rear through a horizontal angle from 45 degrees to the left to 45 degrees to the right of the longitudinal axis of the vehicle."
So, in short, it would seem I need a seady burn surface mount external lighthead that is at least 4.5 square inches with a horizontal viewing angle of 45%. Any thoughts?
As pictured here:
http://www.akardam.net/temp/3rdlight.jpg
The shell I have on my truck has the 3rd brake light handing down in the back window. This is precisely where I wish to place my nifty-rific traffic advisor. So, what I thought, is I could get a simple red no-smarts surface mount LED lighthead to place on the back of the shell above the rear window.
Caveats:
1. The current factory solution uses two bulbs and is fused with a 5w ATO fuse. Any replacement should fall within those power specs (so I can use the existing wiring).
2. As you can see from the pic, while on the outside there's this nice flat space to work with, on the inside there's part of the framing that runs right up the middle. Thus, whatever solution I chose (whether one long lighthead or two smaller lightheads side by side) need to be able to put mounting and power not through the center (I really don't want to drill through that rib there).
3. The back of the shell tips forward. It's not much, no more than a couple degrees, so unless I wanted to make some sort of bevel to install the lighthead in a perfectly vertical alignment, whatever solution I choose would have to have a wide enough off-axis light level to be usable and safe. A bit of digging around located the following information:
From CVC 24603 http://www.dmv.ca.gov/pubs/vctop/d12/vc24603.htm :
"(h) Any supplemental stoplamp installed after January 1, 1987, shall comply with Federal Motor Vehicle Safety Standard No. 108 (49 C.F.R. 571.108)."
From 49CFR571.108 S5.1.1.27 http://squid.law.cornell.edu/cgi-bin/ge ... &TYPE=TEXT :
""1) Shall have an effective projected luminous lens area not less than 2903 square mm. (4 & 1/2 square inches)." and "(2) Shall meet the visibility requirements specified in S5.3.2(c)."
From 49CFR571.108 S5.3.2(c):
"(c) A high mounted stop lamp must have a signal visible to the rear through a horizontal angle from 45 degrees to the left to 45 degrees to the right of the longitudinal axis of the vehicle."
So, in short, it would seem I need a seady burn surface mount external lighthead that is at least 4.5 square inches with a horizontal viewing angle of 45%. Any thoughts?