Cab Light Install

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RPO677

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Thanks to the OP for such a detailed write up. I’ve collected correct GM pieces to do this addition on my 99 GMC.

In reading through the posts, I understand the dash harness plug is buried deep for my model year and not as accessible as earlier models. Can anyone provide detailed guidance as to where the plug is located or if there’s an acceptable wire to piggy back off of at the fuse block?
 

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Drewskis94

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Thanks to the OP for such a detailed write up. I’ve collected correct GM pieces to do this addition on my 99 GMC.

In reading through the posts, I understand the dash harness plug is buried deep for my model year and not as accessible as earlier models. Can anyone provide detailed guidance as to where the plug is located or if there’s an acceptable wire to piggy back off of at the fuse block?
Where did you find an OEM harness?
 

Dangrus4060

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Sorry for bringing up an old tread, again, but i recently decided to add roof marker lights to my 96 K2500HD ECLB.

PART 1 of 4...

I got the kit from LMC... Amber covers, bases, plug sockets, screws, metal nuts... and adding LEDs (leftovers when added LEDs to all my other exterior lights).
I went thru the factory service manual to see how the wire harness was integrated in the cab harness and found out that its actually incorporated in with the EC mirror with compass and vanity light harness, which I recently got from a 96 Tahoe along with the overhead console and overhead reading lights, so I thought this will be an easy upgrade! They appear TAN in the pics due to lighting, but they are GREY!! I have all the wiring for the OH console and reading lights but not enough room for pics.

Gonna attach pics of the lights, harnesses, mirrors, etc, along with the wiring diagrams and pinouts at the convenience center.

NOTE! this info is from the 96 GMT400 factory manual and may NOT be the same for other years!

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NOTE! The Tahoe did not have the rear AC setup, so the switch panel just has a filler panel in its place! Perfect for the pickup!!

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The mirror/Vanity harness is completely plug and play... runs along front edge of roof, down under the cover of the A pilar, and down to the convenience center into the center socket along top row labeled GREY.

I will soon be pulling the headliner and taking it to be redone... I will add all these items while I have it out along with drilling the holes in the roof... Thanks to GINGER and 88GMCTruck! :) The HOLE DIAGRAM is what I've waiting for... no truck in junkyard with cab lights to get my own measurements from...:confused:

Will have to continue with another posts ... limit 5 pics...
 
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Dangrus4060

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PART 2 of 4

The cab lights are plugged into the GREY connector of the Vanity harness with the Orange wire. I found a White wire from another harness in a box of harnesses I had... and added to the GREY plug.

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The grounds for the lights will tie into the black GROUND wire on the WHITE plug.

I grabbed additional wires (WHITE, BROWN (power supply), and BLACK (grounds)) to splice to the grounds and power supply of each light.

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Here are the light assemblies from LMC... with are actually DORMAN parts...

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to be contunied...
 
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Dangrus4060

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PAET 3 of 4

Add'l LMC light kit pics...

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The BROWN wires will be attached to the WHITE poer supply wire and the BLACK wires will all be combined with the BLACK ground wire of the Vanity harness.

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These are the supplied metal nuts from LMC... I will have to verify the hole size required later...

to be continued...
 

Dangrus4060

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PART 4 of 4

Here are the wiring diagrams and plug pinouts from my 96 factory manual. NOTE !! Other years may be different, so check your wire colors on your convenience center plugs. (I would think the 96-00 GMT400 models would be the same, but please check!)

Upper center GREY (2-ports) is for the ORANGE (plug A) vanity feed and WHITE (plug B) cab roof light feed...PLUG #C219 (which will attach to the supplied BROWN plug wires).

Upper right one row down NAT (1-port) is for the GROUND (plug A) ... PLUG #C220

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Back side of Convenience Center with pinout numbers...

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Pinout numbers chart...

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Power supply (WHITE wire #45) diagram with pinout numbers...

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GROUND circuit (BLACK wire #150) diagram with pinout numbers... this is where all the BLACK wire leads from the lights sockets will be attached.

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The 2nd NAT plug on the harness with PINK (port A) and GREEN (port B) wires is for the EC Mirror with Compass - Plug #218

The 2 harnesses will be combined into one to look and install like factory... even though noone will ever see it once installed, but that is how I roll!!! will add more pics as I progress...

Thanks again to GINGER and 88GMCTruck for initiating this thread and supplying the original info...
Hope my additional pics and instructions will be useful/helpful to any and all that will eventually do this same mod...
 
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Dangrus4060

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SCORE!!!! found a 96 K3500HD in the junkyard last weekend with the complete cab light harness with the compass/mirror and lighted vanity sunvisors plugs all in one piece!!!! Removing from the roof was no problem, but didnt bring a socket set with me and struggled to get harness out from behind dash but got it out!!!

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Dangrus4060

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Continued...

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Got the factory hole patterns from another truck in the yard as the donor truck had the short overhead console and i have the long one to go in.

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Also, the pattern for the larger dome light/reading lights for the back seat area.

Can't wait to get the m installed!! I will be getting my headliner and OH console fabric redone while it is out.

Thanks again to OP for exterior hole pattern for roof cab light installation!!
 
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