Correct holes for cargo lamp and switch mounting

Ellie Niner

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My 1986 K10 came to me about 20 years ago with a cargo light, dealer or owner installed with Scotchlok connectors going directly to the dome light. Since the truck is in pretty decent original condition, I want to install the thing correctly, making the holes for switch and lamp housing look factory. I do have a correct switch, harness, and all the other goods needed, but the project has been on hold for long enough that I no longer have any trucks so equipped in the wrecking yards to scope out to refresh my memory. Does anybody have any pictures of the holes in the cab and the plastic trim panel the switch goes into? I do know the proper location for the switch.

Also, is the inner roof panel changed quite a bit between 1983 and 1984, when GM changed the dome light housing from being recessed with a 1004 bulb, to protruding with a 211-2 bulb? I know the earlier setup uses staggered holes and spacers... figured this would be a good time to switch to the better looking (to me) earlier style dome light, as my current one is pretty crispy.
 

RoryH19

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My 1986 K10 came to me about 20 years ago with a cargo light, dealer or owner installed with Scotchlok connectors going directly to the dome light. Since the truck is in pretty decent original condition, I want to install the thing correctly, making the holes for switch and lamp housing look factory. I do have a correct switch, harness, and all the other goods needed, but the project has been on hold for long enough that I no longer have any trucks so equipped in the wrecking yards to scope out to refresh my memory. Does anybody have any pictures of the holes in the cab and the plastic trim panel the switch goes into? I do know the proper location for the switch.

Also, is the inner roof panel changed quite a bit between 1983 and 1984, when GM changed the dome light housing from being recessed with a 1004 bulb, to protruding with a 211-2 bulb? I know the earlier setup uses staggered holes and spacers... figured this would be a good time to switch to the better looking (to me) earlier style dome light, as my current one is pretty crispy.
This is a pic from a 79.
I have an 87 r10 and 78 k10 with factory installed cargo lamps too. But I would have to take pics.

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AuroraGirl

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I don’t know where the switch mounted but my 78k10 also had it and the switch is not on the truck atm. There are coat hooks, bucket seats, over head…console.. that word works, a sunroof, and a different slider so I have a feeling that the switch original position would be hard to assume if it was still there. Lol
 

Ellie Niner

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Right on, and thanks for the replies! It looks like whoever installed it managed to get the outer holes in roughly the right place, but then they just popped a third hole in a random location... should be a decent place to start a rectangular cutout. Any chance of getting a measurement of the cutout?

^ All of the cargo lamp switches I've encountered were on the above and just forward of the driver's side seatbelt anchor for the shoulder harness.
 

AuroraGirl

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Right on, and thanks for the replies! It looks like whoever installed it managed to get the outer holes in roughly the right place, but then they just popped a third hole in a random location... should be a decent place to start a rectangular cutout. Any chance of getting a measurement of the cutout?

^ All of the cargo lamp switches I've encountered were on the above and just forward of the driver's side seatbelt anchor for the shoulder harness.
Does the cut out retain a tab or is it just the size for the wires? If tab you have a thing to measure for the size
 

Ellie Niner

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Does the cut out retain a tab or is it just the size for the wires? If tab you have a thing to measure for the size
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Sorry for the fustercluck loading images on the first try, but this is what I'm working with (The fourth image is of switch installed in someone else's truck). No tabs of any sort, but there's a rough locating mark on the backside of the plastic trim. It does look like the hole *might* be visible if you cut it as big as shown, and it looks like the switch is set up for a rectangular cutout. I presumed there would already be a hole for switch in inner cab structure, but not so.
 

AuroraGirl

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Sorry for the fustercluck loading images on the first try, but this is what I'm working with (The fourth image is of switch installed in someone else's truck). No tabs of any sort, but there's a rough locating mark on the backside of the plastic trim. It does look like the hole *might* be visible if you cut it as big as shown, and it looks like the switch is set up for a rectangular cutout. I presumed there would already be a hole for switch in inner cab structure, but not so.
i actually meant the back of the cab. like is there a reason the rectangle is there or is that just an access for assembly. If so, you could cut a smaller opening and just better fish it. can always cut larger cant uncut so easy
 

Ellie Niner

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i actually meant the back of the cab. like is there a reason the rectangle is there or is that just an access for assembly. If so, you could cut a smaller opening and just better fish it. can always cut larger cant uncut so easy

Gotcha. I think the rectangular hole is there to fish the wires up between the inner and outer roof panel. The only access you have to do this is down by the left rear speaker, the dome light hole, and this one. And yep. Un-cutting sucks! ;)
 

mtbadbob

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The switch hole is round in both the trim panel & sheetmetal. It's about 7/8"-1" diameter, bigger than the 2 connectors, but inside of the screw holes obviously. I recently replaced my cargo light/dome light harness with a nice oem out of a boneyard truck, as mine was hacked & okie rigged. They are a b*tch to fish through the cab, my recommendation is to remove all the connector plugs off the wire and tape the pigtails to the main wires to avoid them hanging up. I can measure my old cargo light seal for the cut-out dimensions if you still need to know how big to cut the hole. The 2 outer holes on the outside of the cab are for threaded inserts for the cargo light.
 

73c20jim

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Dave M

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wHERE DID YOU GET THE BUILD SHEET BOOK????
I was reading this thread and wondered what the cargo lamps were worth, so I looked on ebay and there was the picture. Thought it was good info to share. Cheaper repo lamps at The Truck Shop.
 

mtbadbob

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wHERE DID YOU GET THE BUILD SHEET BOOK????
That is an Assembly Manual. Great to have if you can find one. I have one for my 442, tells you EVERYTHING!
 

Ellie Niner

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The switch hole is round in both the trim panel & sheetmetal. It's about 7/8"-1" diameter, bigger than the 2 connectors, but inside of the screw holes obviously. I recently replaced my cargo light/dome light harness with a nice oem out of a boneyard truck, as mine was hacked & okie rigged. They are a b*tch to fish through the cab, my recommendation is to remove all the connector plugs off the wire and tape the pigtails to the main wires to avoid them hanging up. I can measure my old cargo light seal for the cut-out dimensions if you still need to know how big to cut the hole. The 2 outer holes on the outside of the cab are for threaded inserts for the cargo light.

I was thinking it's gonna be a bit of a pain to fish those wires, so I can see why they likely made the hole so big on the back of the cab; mine actually did have a cargo lamp sorta installed with just those three holes in the cab. And yes, I could still use those measurements. Much appreciated!

 

Ellie Niner

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Thanks for posting that! I have just about all of the factory literature for my truck, but no assembly manual. I fortunately got all of the stuff I needed back before GM discontinued the parts... I'm using my old lamp housing, wrecking yard for the switch and harness- the rest is new.
 

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