Cab roof lights

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

84GMCSierra

Full Access Member
Joined
Feb 26, 2023
Posts
296
Reaction score
353
Location
Central Arizona
First Name
Paul
Truck Year
1984
Truck Model
C2500
Engine Size
350
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
 

Attachments

  • BEEB5FF4-1EDC-4C14-9F78-1DC38A8E9815.jpeg
    BEEB5FF4-1EDC-4C14-9F78-1DC38A8E9815.jpeg
    117.2 KB · Views: 143
  • 1EA0C84D-8A22-40ED-96CD-460D88768092.jpeg
    1EA0C84D-8A22-40ED-96CD-460D88768092.jpeg
    118.7 KB · Views: 143

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,659
Reaction score
6,602
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
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.;)
 
Last edited:

84GMCSierra

Full Access Member
Joined
Feb 26, 2023
Posts
296
Reaction score
353
Location
Central Arizona
First Name
Paul
Truck Year
1984
Truck Model
C2500
Engine Size
350
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.....
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,422
Reaction score
4,482
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,70,48
Truck Model
Suburban k10, bonanza k10, c30 C&C, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350
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?
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
28,966
Reaction score
23,484
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
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

Full Access Member
Joined
Feb 26, 2023
Posts
296
Reaction score
353
Location
Central Arizona
First Name
Paul
Truck Year
1984
Truck Model
C2500
Engine Size
350
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

Full Access Member
Joined
Dec 28, 2014
Posts
3,422
Reaction score
4,482
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,70,48
Truck Model
Suburban k10, bonanza k10, c30 C&C, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350
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.
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
5,882
Reaction score
9,623
Location
Washington
First Name
Todd
Truck Year
1986
Truck Model
K20
Engine Size
454
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

Full Access Member
Joined
Feb 26, 2023
Posts
296
Reaction score
353
Location
Central Arizona
First Name
Paul
Truck Year
1984
Truck Model
C2500
Engine Size
350
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.
 

Attachments

  • IMG_5793.JPG
    IMG_5793.JPG
    237.5 KB · Views: 64
  • IMG_5794.JPG
    IMG_5794.JPG
    191.3 KB · Views: 65

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
5,905
Reaction score
7,252
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
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

Full Access Member
Joined
Feb 26, 2023
Posts
296
Reaction score
353
Location
Central Arizona
First Name
Paul
Truck Year
1984
Truck Model
C2500
Engine Size
350
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?
 

Attachments

  • IMG_5814.JPG
    IMG_5814.JPG
    91.4 KB · Views: 36
  • IMG_5815.JPG
    IMG_5815.JPG
    104.6 KB · Views: 36
  • IMG_5816.JPG
    IMG_5816.JPG
    87.4 KB · Views: 34
  • IMG_5813.JPG
    IMG_5813.JPG
    61.4 KB · Views: 35

Forum statistics

Threads
41,858
Posts
903,637
Members
33,372
Latest member
83elcowes
Top