Truck Bed Perimeter Light project

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Hi All – Have a project Im trying to make happen – wire up some GM OEM Bed Perimeter Light kits. I don't think these are under any "strict" legal constraints, as they are for Accessory lights, mounted up under the pickup bed lip, and provide indirect lighting, downward into the bed. These lights are not combined with any other lamp on the vehicle, thus, If I am correct, I believe these fall under the US regulations for CARGO LAMPS, in but I defer to the experts.

I came across several GM truck bed perimeter lighting kits for almost free, so I couldn't pass them up, as they are normally quite expensive. I can't post pics, and don't use file sharing sites, so I post a link to the GM OEM product on Amazon.
GM Perimeter Bed Lighting

These kits are meant to be used 1 per truck, and come with a pair of sealed lamp housings, and a y-harness, that plugs into a chassis block, using only power and ground. The lights have circuitry on the boards with the SMD LEDs, so perhaps they have the resistors built in, given how simple the wiring harness is? The lights also have a 12.8V stamping on the back, so perhaps that is the forward Voltage (these are automotive kits, after all)?

I was hoping to splice the two sets of lights together, and adjust the schematic to use all 4 in parallel, with 2 SPDT switches (1 in the cab, 1 in the bed), so that a loss of any of the light assemblies would not affect the others…is this a bad idea?

Is there a way to limit current in case of a loss of light assemblies, so as not to get a current overload on the remaining lights?

How might I actually measure the operating current – hook up one set and measure the current to each light using a clamp/voltage meter?

Are there any considerations that need to be taken?

I didn't think I needed a driver, since they appear simple and <I believe> low current applications, but obviously I am not an electrical engineer, nor terribly well versed in LED circuit design.

I have drawn up a draft schematic, but I cannot post that up to the forums yet…

Thanks for any and all comments!
David
 
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Alaric Darconville

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Any of the current-limiting circuitry may be right at the lamp module itself, so splicing in several to use the same QC is probably fine. The complex portions of such an electrical circuit should logically be placed at the fixed location-- a wiring harness like that is designed to be connected/disconnected at will, so it would make more sense to make the connector end simply a connector end and not have complicated circuitry in it.
 

Lynx_Arc

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If you want to truly limit current put fuses inline with each light that blow when current is exceeded. I think the only issue you should have is if your wiring is inadequate and causes excessive voltage drop such that when one or more lights are turned off the voltage/current is higher to the Lights than with all operating at once.
I would consider putting a 3 way switch setup so you can turn it on/off regardless of where you are at in/out.
 

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Good point, Alaric...FYI, I tried to "reply with quote", but my spacebarstoppedworking :sssh:

I think I saw some other threads that mentioned this; maybe it is a bug on our machines?

Lynx - inline fuese is a good suggestion - I plan on building the entire circuit before I install it, so I'll be able to use this. I <thought> my idea to use 2 SPDT switches was a design that would allow the circuit to be toggled from either switch, like light switches at either end of a set of stairs - did I have my terminology wrong?

when I can post diags, I will post my schematic

thanks much for your comments guys
 

Alaric Darconville

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If you want to truly limit current put fuses inline with each light that blow when current is exceeded
That's probably going overboard, and there shouldn't be any overcurrent unless these modules develop closed shorts.

I think the whole "overcurrent" thing is a red herring. A module failing won't suddenly send extra current to the remaining modules.
 

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copy that regarding overcurrent concerns, Alaric...so I have drawn a schematic, running the lights in parallel, with 2 SPDT switches, in order to allow switching power on and off from either in the bed, or in the cab, and to ensure that losing one light wont kill the entire set of lamps...do you think this is not worth the effort (parallel vs serial circuit to power lamps)? I plan on the dual switch design either way.
 
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Alaric Darconville

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I can almost bet that in the standard 2-module set, they're already in parallel. Just wire in the second set in parallel very near that quick connect so they share the one connection. Since a complete set can be used for either the driver or passenger side, you can put one set on the driver side, and the other on the passenger side.
 

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Interesting thought Alaric - I'll take a look at the harness and main plug and go from there

UPDATE: ok I couldn't wait; I pulled one loom apart...they are wired in parallel :bow:
 
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Here is a link to some close ups of the wiring harness, with the wires exposed to show parallel...

Also in the share is a schematic of a 2 SPDT switch design for use with the 4 lights - is this correct?

oops here is the link: https://goo.gl/photos/zBQ5Tnt6j5D8uWFs7
 
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Lynx_Arc

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Good point, Alaric...FYI, I tried to "reply with quote", but my spacebarstoppedworking :sssh:

I think I saw some other threads that mentioned this; maybe it is a bug on our machines?

Lynx - inline fuese is a good suggestion - I plan on building the entire circuit before I install it, so I'll be able to use this. I <thought> my idea to use 2 SPDT switches was a design that would allow the circuit to be toggled from either switch, like light switches at either end of a set of stairs - did I have my terminology wrong?

when I can post diags, I will post my schematic

thanks much for your comments guys
http://www.electrical101.com/3way-switches.html
Here is a page that explains it well enough with schematics.
SPDT is correct (Single Pole Double Throw). The only problem with 3 way switches is you can't wire an indicator light with them to show that the light is on if you want an indicator light you would have to run a separate wire from past the switches near the bulbs to show they are on or not.
 

Lynx_Arc

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That's probably going overboard, and there shouldn't be any overcurrent unless these modules develop closed shorts.

I think the whole "overcurrent" thing is a red herring. A module failing won't suddenly send extra current to the remaining modules.
If you have only one wire connecting to the switches then separate wires to each light and the one wire is too small a gauge then it could under heavy current add considerable resistance and when the load is dropped to half the voltage could rise. If you have adequate main wiring then this would not be a concern. Often people put wiring in for one set of lights to their switches and just add one another set of lights to the same switches and main harness which isn't rated for double the load.
 

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I think I found some appropriately physically sized and rate switches that are
12v 15a DC, SPDT, ON-ON, illuminated rocket switches - one I found has LEDS on either end of rocker

Maybe this solves the led indicator issue for in the cab...

I might use a one of those colored ring-lit waterproof metal push buttons for in the bed
 
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This is a low current application with maybe 20 or 22 awg wiring...I could upgrade all of it but I don't think there will be much current overall

If you look at the pictures in the link you can see they supplied very small gauge wiring

I'm going to run parallel from close to the power source, so hopefully this isn't an issue

Maybe upgrade it to 18 gauge?
 
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Lynx_Arc

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I think I found some appropriately physically sized and rate switches that are
12v 15a DC, SPDT, ON-ON, illuminated rocket switches - one I found has LEDS on either end of rocker

Maybe this solves the led indicator issue for in the cab...

I might use a one of those colored ring-lit waterproof metal push buttons for in the bed
It depends on how the indicator is wired as with a 3 way switch setup you need to take the voltage after both switches for an indicator light so if it doesn't have separate wires for the indicator then it may be on when the lights are off and may be off when the lights are actually on.
 

Lynx_Arc

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This is a low current application with maybe 20 or 22 awg wiring...I could upgrade all of it but I don't think there will be much current overall

If you look at the pictures in the link you can see they supplied very small gauge wiring

I'm going to run parallel from close to the power source, so hopefully this isn't an issue

Maybe upgrade it to 18 gauge?
You can google wire size charts (gauge) and calculate your total current draw of all lights as it probably is ok from EACH light to where they are connected together at either the common bus or switches then the parallel addiction of the lights adds to the current draw. If you have 4 lights that take 22 gauge then those wires (each) can handle almost an amp while 20 gauge can handle 1.5A. I doubt the wiring is taxed near the limit as when you get low current wiring sometimes they make wires larger than needed just to protect the wires from breaking. If you want a switch in the cab and one in the bed area then you will have to use larger wiring between them and the power source while you may be able to wire the other wires together to the source. I've put alternative wiring in vehicles with switches and tapped off the parking light circuitry to draw (low) power as it is more convenient than trying to run wire and connect to the fuse box and also parking lights are turned off when you leave the vehicle and are on a fused circuit too.
 

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Yes I understand...they may have an led that lights up if either on-on presents a closed circuit...I'm waiting for an answer on that

Your suggestion for larger wires to the cab is well taken - I was planning on just that...I'm taking power from the rear bus plug block under the pickup tailgate...at least I'm thinking correctly in some ways :)

Thanks so much for your inputs
 

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Here are the switches I think I'll use...I found some other switch manufacturers, but they are from distributors that want me to order 20 or 100 of them :(

There are other items I may add to the vehicle, so I will install a 3 slot bezel, to leave room for other options controlled from the cab: Cole-Hersee Rocker Switch mounting set 82159

Two options for the cab switch - Cole-Hersee 58312-RR2, or Cole-Hersee 58328-16...both are On-On, SPDT switches that have dependent indicator lights, so I think they will light up for the circuit when closed (bed lights lit up) in either position

here is the link (same share as above, 4th pic in share) to the switch schematic: https://goo.gl/photos/zBQ5Tnt6j5D8uWFs7

Found a sealed SPDT On-On toggle switch, for the pickup bed: Cole-Hersee 55025-03...I'll have to make a mounting bracket or find a good place to make the mounting hole...

I think it will take a few weeks at least to order these not-very-common switches, but maybe I'll get lucky
 

Lynx_Arc

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Here are the switches I think I'll use...I found some other switch manufacturers, but they are from distributors that want me to order 20 or 100 of them :(

There are other items I may add to the vehicle, so I will install a 3 slot bezel, to leave room for other options controlled from the cab: Cole-Hersee Rocker Switch mounting set 82159

Two options for the cab switch - Cole-Hersee 58312-RR2, or Cole-Hersee 58328-16...both are On-On, SPDT switches that have dependent indicator lights, so I think they will light up for the circuit when closed (bed lights lit up) in either position

here is the link (same share as above, 4th pic in share) to the switch schematic: https://goo.gl/photos/zBQ5Tnt6j5D8uWFs7

Found a sealed SPDT On-On toggle switch, for the pickup bed: Cole-Hersee 55025-03...I'll have to make a mounting bracket or find a good place to make the mounting hole...

I think it will take a few weeks at least to order these not-very-common switches, but maybe I'll get lucky
Here is a supplier I've bought switches from not sure about the shipping as I haven't bought from them for about 10 years.
Here is the PDF that shows you how to choose your switch type
http://www.mouser.com/catalog/specsheets/Otto_K1-K2_Snap_In_Rockers.pdf
and here is the page I think listing all the switches.
http://www.mouser.com/OTTO/Electromechanical/Switches/Rocker-Switches/K1-Series/_/N-5g2q?P=1yzs85aZ1yyh514
I was going to try and find the switches you need but note there is 2 types of illumination: LED and INCAN and some use a pin 4 (independent) and one other pin for power to the LED. If you choose the right 2 switches (one from the power source, second to the lights) you should be able to use the build in lights even the LED variety (which I recommend). I think mouser will ship USPS. The switches come in all sorts of different configurations.
 

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Nice work lynx! I'll engage w Mouser(otto switches) and a Cole-Hersee vendor next week...
 
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