Hardwiring LED light bar

[Phasefive5]

I was wondering if anyone has put a 4th break light on there truck. I had a 2002 Sierra and hardwired/ spliced in a LED light bar that goes underneath your tailgate (with reverse). I have read/ heard that on newer trucks it senses that you are pulling a trailer and you have to wire it into your taillights instead? just curious if anyone has done this or knows if I can just splice the trailer lights and hook it up that way again or if I need to wire it into my tail lights.

Also do I have to worry about damaging or overloading the circuit at all.

Thanks

 

[dgirouard39]

Curious as well

 

 

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[Phasefive5]

Wanting to mount of 2017 Silverado

[newdude]

For doing just a 4th brake lamp:

 

#PIT5314A: CHMSL Wiring For Aftermarket Bed Cap Topper - (Dec 12, 2016)

 

2016-2017 model years

Perform the following recommendations based on vehicle configuration:

1. For vehicles built WITH Under Rail Bed Lighting Option:

   Trucks equipped with the under rail bed lighting option will already have the female side of the X400 connector. Obtain an appropriate length of 18 ga wire to run from the X400 connector up to the CHMSL wiring for the cap or topper. Use terminal part # 60012931 in AFL Tray 21, along with wire seal part # 60994015 in AFL Tray 21 and connect it to one end of the wire. Disconnect the X400 connector and remove the rubber cavity plug in pin position 4 and discard. Install the terminated lead that was just made into the X400 connector pin 4. Run the wire up to the CHMSL for the cap or topper and connect. The ground for the cap or topper CHMSL will need to be made to an appropriate ground.

2. For vehicles built WITHOUT Under Rail Bed Lighting Option:

   Trucks not equipped with the under rail bed lighting option will have a dummy X400 female connector, which will be removed and discarded. The female side of the X400 connector is not available separately, but can be obtained by ordering the under rail bed lighting harness GM part number 23327843. The harness will come with terminals/wiring in pin positions 1 and 6. Remove the wiring and terminal from pin location 1 and discard. Move the rubber cavity plug from pin position 4 and reinstall it into pin position 1. Obtain an appropriate length of 18 ga wire to run from the X400 up to the CHMSL wiring for the cap or topper. Use terminal part # 60012931 in AFL Tray 21, along with wire seal part # 60994015 in AFL Tray 21 and connect it to one end of the wire. Install the terminated lead that was just made into the X400 connector pin location 4. Pin 6 is a ground circuit that is used for the under rail bed lighting and it can also be used to ground the CHMSL for the cap or topper if the wire gauge size in the connector is of the proper size for the CHMSL in the cap or topper. If the wire gauge size is too small, any of the following can be done:

• Make a second wire as described above. Then, remove the wiring from pin 6 and discard. Install the new terminated wire in position 6 for the ground and run it up to the CHMSL for the cap or topper and connect.
• Remove the wire and terminal from pin 6 and install a rubber cavity plug.
• Cut the wire for terminal 6, leaving a couple inches of wire, and seal the end of the wire.

Note: The terminal removal tool for the female side of the X400 connector is J-38125-212.