Secondary Cargo Switch in the bed

[Thompyt88]

Interesting mod.  Why didn't you connect to the switch in the cab on the switch/BCM side and run the wire to the momentary switch in the bed, then have the other side of the switch run to ground?  That would be the most simplified means to meet the intent, and there is actually no power on the line. 

[DasGoob]

I am assuming that getting behind the dash to tap into the actual switch is far harder than to place a pin into a Body control module under the dash.  I could be wrong.  

 

I want to do this mod in conjunction with the additional bed lights, and I have everything done with the exception of putting the wire into the BCM X2 harness.  My issue is this.... my BCM connectors look different than what is posted here and thus I cannot match it.  Does anyone have the map for the cargo lamp line to the BCM for a 2024 Silverado LTZ?  

[DasGoob]

Well just found it in the Electrical Body Builder info for the '24 trucks.  It is now X1 and pin 19.  Out i go to try to find it again:

[DasGoob]

Okay, mine is complete.  For some reason in my feeble brain I had it that the cargo lamp switch was in the center console, even though I have activated the cargo lamps multiple times.  Brain fart.  Once I aligned my brain, I did decide to go for the switch on the headlight switch assembly.  Mainly this is easier to get to than a BCM, won't cause issues if you disconnect the X1 connector on the BCM, and is better hidden, so if warranty work is needed, you don't have to worry about a technician trying to tell you that the warranty is void for a wire plugged into the connector.  

 

So, I went at it.  By removing the panel under the steering wheel to expose the fuse box, the side dash panel facing the door, you uncover 2 of 3 screws needed to remove the switch assembly for the transfer case and headlights.  Now gently pull on the glossy dash bezel and it will come free from the dash enough to expose bolt number 3.  Once you carefully remove it without overstressing the bezel, the switch assembly comes out easily giving you fantastic access to the switch and wiring.  

 

From here it is easy sailing.  Pin 4 on the connector is the signal wire to the BCM.  Remember, this view below is as if you unplugged the connector from the switch and you were staring at it.  If you are looking from behind, it is a mirror view with Pin 1 on the left and pin 12 on the right.   When you press the switch, it grounds pin 4 to pin 8, turning on the lights.  I merely put my wire from by bed switch (with the solid wire end soldered to the wire as earlier suggested) into the back of the connector with the grey wire in pin 4 and then taped it to the wire bundle to hold it securely.  Tested and worked great.  Switch in the bed now turns on cargo lamp, bed lamps, and the extra bed lamps that I have fed from a relay from a method in a different thread.  

 

Hope this helps someone.  

[DasGoob]

Final Post.  Attaching schematic and worksheet.  

Additional Bed light schematic.pdf

[AlanK]

Added Cargo Bed LED strip lights and a Trailer Spoof circuit to my '23.

 
Used the headlight switch wire described by DasGoob above.  Works great.

It was easy to get to the cargo bed switch wire in the dash.  It took more time to run it under the truck.
Still easier for me than trying to access the BCM under the dash.

Strip LEDs are from amazon.  They are mounted on the underside of my bed cover rails (aluminum) using
double sided tape and Lexel caulk (Lowe's) to seal the deal.  No drilling needed.

 

Trailer spoof is to turn on the left and right turn signal cams.  I like seeing what is beside
me before changing lanes.  Turn off switch also included.  Resistors draw enough current for
the BCM to think a trailer is attached.  Diodes are to keep the circuits isolated.

 

Used similar switches in the bed (12mm diam) as above and they fit nicely in the bed stake bolt holes on left and right fender sides with a few stainless steel washers.

 

Thanks to all in this thread.  Difference is night and day!  See on and off pics.

[VE4ADB]

So i'm by no means an electrical guy, i know enough to be dangerous, i was going to order the kit from gen5diy however the shipping to Canada is more then the price of the kit plus conversion. so if i follow this right all we are doing is essentially grounding pin 18 ( i believe it was) on the blue bcm harness and adding an inline switch in the box? forgive me if i missed a step. 

I have the boost auto mirror and cargo light mod if that matters.

 

Thanks all

[AlanK]

I used pin 4 on the headlight switch in the dash.  Easier to get to than me crawling under the dash to get to the BCM.  Here is the schematic info for both sides - headlight switch in dash and BCM under dash.

 

[AlanK]

Looks like pin 19 on BCM.  You are adding a momentary contact switch in parallel in the bed to duplicate the cargo switch function.

 

What's nice is it keeps the 10 minute timeout to automatically turn off the lights if you forget.

 

Push on.  Push off.  Sweet.

Edited March 15 by AlanK
added info

[VE4ADB]

Awesome thank you ill try this out in the next few days. Just waiting on a switch!

[AlanK]

I used this MOM switch mounted in the bolt hole where the post for a rack would be inserted.  No drilling needed.  I did use two stainless steel washers to cover the entire hole.

 

You can also tap the ground on the existing cargo lights to run one less wire.

 

https://www.amazon.com/dp/B09BKWMNJ9?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

 

73, N1WV

Edited March 16 by AlanK
added info