Cab roof lights

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84GMCSierra

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Good morning everyone. I've added these roof lights to my truck, and have one wire going to power, but it's supposed to go through a separate rocker switch. I want to hook into my light switch so they are on whenever the lights are on, but not sure how to do this. Do I tap into the light switch harness for the park lights? Im guessing since there are screws through the metal roof, they should be grounded, or do I need another ground somewhere? Thanks
 

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SquareRoot

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Holy Jesus, mother of God! Apparently he didn't know the roof consists of an inner and outer panel. Stick to smooth roads lest you die from a stab wound to the skull. Standing by to see the DIN stereo installation pics.;)
 
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84GMCSierra

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Oh my. Would you care for pointers on a much tidier and safer installation?

But yes, you can get power from any fused park/tail source.
What do I need to do? This is a set from LMC and this is how it says to wire it. I thought it was weird but.....
 

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What do I need to do? This is a set from LMC and this is how it says to wire it. I thought it was weird but.....
Not calling you a liar or stupid or anything, lmc definitely isnt perfect so. Do you still have those instructions for our viewing pleasure?
 

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What do I need to do? This is a set from LMC and this is how it says to wire it. I thought it was weird but.....

I can't tell if you have screws poking through the inside of the roof, but if they are, definitely use shorter screws. Also, those scotch loc type connectors are failure prone. Solder and heat shrink are the best method of connection, but even butt connectors are much better than scotch locs, especially if they are the heat shrink type. Lastly you should fish the wiring through the roof (it's two layers) and down the driver's side A-pillar so it's not exposed and dangling.
 

84GMCSierra

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I can't tell if you have screws poking through the inside of the roof, but if they are, definitely use shorter screws. Also, those scotch loc type connectors are failure prone. Solder and heat shrink are the best method of connection, but even butt connectors are much better than scotch locs, especially if they are the heat shrink type. Lastly you should fish the wiring through the roof (it's two layers) and down the driver's side A-pillar so it's not exposed and dangling.
Screws aren't poking through. What is the best way to run the wiring between the roof layers? Fishing line? How would I attach each light to the main wire? Sorry guys. I guess I should have done some research before doing these lights.
 

PrairieDrifter

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Screws aren't poking through. What is the best way to run the wiring between the roof layers? Fishing line? How would I attach each light to the main wire? Sorry guys. I guess I should have done some research before doing these lights.
Mechanics wire, through the drivers a-pillar. Its just kind of thin smooth wire. Its a pain in the ass, tape the wire to the mechanic wire and pull it through, you need enough slack to connect the lights to the harness through the holes underneath them, that's why the factory cab lights have such a large hole.

Im sure they made the harness outside of the truck and carefully shoved the top half in then pulled each connector out each light hole then pulled the main run down the a-pillar.
 

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Just install a headliner, to hide the oopsie.
And ditch the red thingys if they’re scotch locks.
OE cab lights run off the parking lamp circuit. Tie in as close to the headlight switch as possible IMO.
And honestly, I kinda overkill on this but I like reducing loads on antique electrical systems, so I’d prolly run a relay. Or relay the headlights and keep the ambers direct wired. Keep some heat out of the headlight switch.
 

84GMCSierra

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Not calling you a liar or stupid or anything, lmc definitely isnt perfect so. Do you still have those instructions for our viewing pleasure?
Ok guys. I finally found the destructions, I mean instructions for my cab lights.(They fell behind my bench). Anyways here's how they say to wire them up. I'm all ears on a much better, safer way to wire them up. How can I get the wiring between the roof panels, and still have them all connected? I appreciate any and all help and tips on getting these things lit up. My truck didn't come with a headliner either, or a dome light.
 

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Didn’t read the paper, but what do the rubber grommets at the base of the lights look like? Maybe use the inner hole of the grommet as a template or some reasonably sized hole that you’ll have success with a fish. Then it looks like you pull a single 12v+ wire up and splice each light onto the wire. For bonus points you fish a common ground wire up at the same time so you aren’t relying on the light’s sheet metal screw to have good continuity on your ground path. There is a ground behind your dash close to the drivers side door hinge area. It has 6 or 8 spade terminals iirc. You should also clean that up while you are in there.

Grit Dog’s comment about relaying your lights will help all of your lights out. As it is from the factory, all the light loads are drawing through your light switch and now you’ve just increased the load. Putting the headlights on relays triggered by their old original conductors is an upgrade worth doing. It only costs two relays and some 12ga wire. It’ll give you the opportunity to clean up/inspect the headlamp harness as well.
 

84GMCSierra

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I've seen the block with the terminals on it, kind of figuring they were for grounds. Here is one of the lights, broken down so you can see what I'm working with. If these don't end up working, I'll find a set of originals, a pattern, and install those. I like these since they are low profile. Last pic is of the connectors. I'm guessing by the comments that they are the "Scotch-Lock", and aren't any good?
 

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