Secondary Cargo Switch in the bed

[Josef]

If you’re not scared of tapping into the factory wiring most canopy setups run a ground off the drivers side taillight.  Just another option.  

[RedLT]

On 3/16/2022 at 10:47 AM, Thomas Arias said:

@RedLT @TA^Guy - Yes! The dash is a momentary switch sending ground to the BCM. And great news, all the info I found in the docs is correct and I was able to get it to work  

 

I got way ahead of my self and ordered all my stuff before even testing it out, but it was worth it in the end. I hate splicing oem wires so I went a little over board. Here's what I used:

• 7-way Harness splitter to tap into the trailer 12v power and Ground
  • https://www.amazon.com/dp/B09BMNLX6S/ref=cm_sw_em_r_mt_dp_9T8ZKHTT2KFH8JA21CHK?_encoding=UTF8&psc=1
• Momentary Button for the bed
  • https://www.amazon.com/dp/B07P6TY9JD/ref=cm_sw_em_r_mt_dp_AWRDX4FK7HCXT66F1DBF?_encoding=UTF8&psc=1
• Spool of wire, and I used it all
  • https://www.amazon.com/gp/product/B000NV0FGU/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
• Wire loom to protect the wire. Almost used it all. Still have about 1-2 feet left
  • https://www.amazon.com/gp/product/B001GN6QCG/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
• And some extra stuff I had laying around
  • Electrical tape
  • 22 gauge solid wire
  • heat shrink

I'd love to give credit to a post about running wire through the firewall but I can't seem to find it anymore. I went through the the rubber grommet on the driver side. I used my smallest drill bit to manually hand drill a hole. Then shoved a clothes hanger with the wire taped to it. I found it inside under the steering wheel behind a thick foam pad. The clothes hanger helped me find it quick since it was poking out and pushing on the foam piece.

 

 

I then ran the wire loom (with wire already in it) from the engine bay down to the frame then to the back. This took the longest and there's a few paths to take. I spent too much time making it pretty and zip ties. I avoided hot parts and exhaust. I should have jacked up the rear end or something, but I crawled underneath instead and man am I sore today. It's a very tight squeeze (for me). And make sure to underbody wash before you start. I live where the roads are salted white and I had a lot of salt falling on my face. Not pleasant. So I ran wires down, hugging the frame and zip tied to another harness already going towards the bed. I got to the rear fender and ran wires up behind the tail light and continued to the hand grab and wired up my switch. I removed the rubber plug (19mm) and put my switch in there. A little ugly in plain view looking into the hand grab... but no one looks down there. The rubber grommet picture is the passenger side, but the same grommet is on the driver side.

 

 

 

Then I zip tied the 7-way splitter under the hitch and ran the wires behind the driver tail light. The 12V from the 7-way is hot so I didn't plug in the harness until I finished all my connections. The 7-way harness is bit pricey since it's a full kit to add a 5th wheel connection to the bed, but I rather cut that than my factory harness. So at the tail light, I cut the end off of the 7-way to expose the 7 wires: Black is hot and White is ground. Part 2 for me will be adding more lights to the bed so that hot lead will come in handy later. I taped and heat shrink all wires. But took the white wire from the 7-way and connected that to the other side of the new momentary switch. The switch now has the one wire going to the cab and the second wire connected to the 7-way white wire for Ground. Sorry no pictures  I was tired and frustrated after crawling under the truck for a few hours trying to get my hand in tight places for the zip ties... and forgot to document it all.

 

Lastly, I found my X2 plug. It's blue and pins increment from left to right. I counted backwards from pin 22 and arrived at the grey pin 18 as mentioned in the GM upfitter PDF. More credit to another post that said to solder the wire to a smaller solid wire so I soldered the 16 gauge stranded to 22 solid and shoved it into Pin 18. WORKS GREAT

 

 

 

 

Here is the end result: https://photos.app.goo.gl/3r3LZts9s6UP97NW6. And I'm very happy

 

I now ordered some lights, a relay, and some connector pieces for part 2. Yes, I hate splicing into factory wires so I had to figure out the bed light connectors/adapters so I can cut into my own wires and not the trucks. This will be for another day, hopefully warm and sunny so I can work outside... with no salt falling on my face

• Lights
  • https://www.amazon.com/gp/product/B09KKR6DZK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
• Relay
  • https://www.amazon.com/gp/product/B08D8TSMFV/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1
• MCON 1.2 parts to tap into cargo bed lights
  • 

 

Tom, that is excellent work! Detailed and through and the pics do wonders. Exactly the functionality I was looking for. I'll be ordering parts and will work this in a few weeks. Thanks for bringing back your end results.

 

[GETGONE]

I picked up a waterproof stainless momentary switch from ebay for $5.25 shipped. I'm glad there's the same hole on the passenger side as I have the Multi Flex tailgate and the handle in the bed uses that hole so I'll have to put my switch on the passenger side.

[NightcrawlerZ71]

Awesome work and write-up Tom! 

 

If seeing the wire loom bothers you too much, you can buy rail plugs. I feel like they should have came with these from the factory. There are a lot on Amazon, but these are the ones I've bought and I love them. They are very high quality 3D printed. The texture matches the factory rail texture very well. 

 

ES ENGINEERED BY SCHILDMEIER Stake Pocket Cover Set for 2019-2022 Silverado/Sierra (Set of 2) NOT 3D Printed https://www.amazon.com/dp/B07KVKN9PZ/ref=cm_sw_r_apan_i_9VE17GNRF40YPAYTGEG9?_encoding=UTF8&psc=1

[Derek99]

On 3/20/2022 at 5:23 PM, Thomas Arias said:

Part 2 is a success! I tapped into the existing cargo light and used it as the trigger for the relay. When the cargo lights turn on, it will trigger the relay to send power to the additional bed lights.

 

Pardon my frustration but the bed lights I mentioned in the previous post, Xprite lights, are awesome from a lighting perspective... but garbage from a wiring perspective. I decided to cut and re-solder the Xprite wiring harness because the Y-splitter where the lights connect to are way too short. I think these lights are meant to be wired from the front of the bed and then ran towards the back. I'm not set up for that because my power and ground from the 7-way harness are tucked behind the driver side tail light. So I cut the adapter off from the Y-Splitter and re-soldered it to the other end. That way, one adapter is on the passenger tail light and then the wire would run down and under the tailgate to get to the driver side tail light. I also cut off the included switch, not needed since these will be triggered with the cargo lights.

 

For the passenger side tail light:

 

For the driver side tail light:

 

 

Then I moved on to the MCON 1.2 parts to tap into the bed lights. I made an extension harness to make sure I wired it properly. The GM cargo light has a '+' and  '-' sign on the male plug. I tested out the fitment of the connectors to the cargo light and marked where the positive end is and made a note of it so I wire it correctly. It's also a good idea to order extra parts, like two of each for experimental reasons. Thankfully that's what I did. I had some trouble figuring out how to insert the pins into the housing. I hope the picture shows you hot wire and ground clearly. It's hard to put it into words but I tried.

 

 

 

 

And the end result... ta da. A huge bundle of wires behind the driver tail light. I miscalculated the amount of wire I needed and ended up with so much hanging out after I soldered everything together. Rather than shortening/redoing everything, I just zip tied the extra back there. No harm really. If you crawl under the rear bumper, you can see a straight shot up to the back end of the tail light. I shoved my arm up there and added a few more zip ties to make sure everything stays put. I zip tied everything to other harnesses back there and to the frame, and to each other. That's not going anywhere!

 

 

Here's another updated video of the end result: https://photos.app.goo.gl/b3K6PHustdKGtcGV7. Enjoy the super clean bed! It hasn't been this clean EVER.

 

Now I wait for some adhesive clips I ordered so I can tuck and hide the rock light wires under the bed rail. This was fun and thanks to a ton of other forums that motivated me to do this mod. Before I started, I slowly gathered a ton of info from the site for each step. Took me hours, and a lot of materials. I need to restock my heat shrink, wires, zip ties, solder, and my sanity/patience. But it is totally worth it and puts a smile on my face.

 

I hope this helps anyone else trying to do the same thing.

 

Thomas,

 I just did a similar install with my 2022 GMC AT4 but I already had the gen5diy switch kit. Also bought 4 rock LEDs for the bed and I have the boost auto cargo reverse jumper installed. 

 

 I have my switch kit installed and after trying to tie the 4 rock LEDs off the existing light they just blinked. So I had to get a relay and powered that off the 7pin trailer harness. Someone was saying to use a diode to stop current flow back from the switch but I separated my switch and relay so didn't think I needed one. I see you grounded your new rock LEDs to the 85 black ground wire.

 

Instead of grounding my 4 new LEDs to 85 relay wire. I grounded them to the existing black ground wire going to the factory bed lights.

 

For some reason everything works now when my truck is off. 

I can hit the key fob and all the security lights come on, cargo bed and 3rd brake light. 

 Or I can hit my new switch and all 6 bed lights come on. But now I cant figure out what's causing my problem when the truck is running. My key fob will not work and security mirror lights aren't staying on.

 

 Do you have the boost auto reverse jumper installed and did you have any issues with your lights not working while the truck is running? Trying to figure out if it could be that ground or a diode I need to fix my problem.

Thanks

[Derek99]

10 minutes ago, Derek99 said:

 

Thomas,

 I just did a similar install with my 2022 GMC AT4 but I already had the gen5diy switch kit. Also bought 4 rock LEDs for the bed and I have the boost auto cargo reverse jumper installed. 

 

 I have my switch kit installed and after trying to tie the 4 rock LEDs off the existing light they just blinked. So I had to get a relay and powered that off the 7pin trailer harness. Someone was saying to use a diode to stop current flow back from the switch but I separated my switch and relay so didn't think I needed one. I see you grounded your new rock LEDs to the 85 black ground wire.

 

Instead of grounding my 4 new LEDs to 85 relay wire. I grounded them to the existing black ground wire going to the factory bed lights.

 

For some reason everything works now when my truck is off. 

I can hit the key fob and all the security lights come on, cargo bed and 3rd brake light. 

 Or I can hit my new switch and all 6 bed lights come on. But now I cant figure out what's causing my problem when the truck is running. My key fob will not work and security mirror lights aren't staying on.

 

 Do you have the boost auto reverse jumper installed and did you have any issues with your lights not working while the truck is running? Trying to figure out if it could be that ground or a diode I need to fix my problem.

Thanks

[GETGONE]

Seriously??? WIRE NUTS ON A VEHICLE???? USE BUTT CONNECTORS!!!

[Derek99]

4 hours ago, GETGONE said:

Seriously??? WIRE NUTS ON A VEHICLE???? USE BUTT CONNECTORS!!!

 

4 hours ago, GETGONE said:

Seriously??? WIRE NUTS ON A VEHICLE???? USE BUTT CONNECTORS!!!

Dude, this was when I was testing it all. I soldered everything with heat shrink when it was done. Was just showing a picture of the relay wiring!

[GETGONE]

I've seen too many videos of vehicles that actually use wire nuts and have found a few myself over the years. It drives me nuts! Glad it was just for testing. I just twist the wires for testing.

[Derek99]

13 hours ago, GETGONE said:

I've seen too many videos of vehicles that actually use wire nuts and have found a few myself over the years. It drives me nuts! Glad it was just for testing. I just twist the wires for testing.

Gotcha, yeah I was having to make sure everything was working like it should with the relay and switch. Wish I could have avoided the relay but probably could have only used 2 additional lights then. 

[GETGONE]

Yeah, the OE BCM doesn't like much if any additional load. I had to add a relay for mine when I added LED cube lights in addition to the multiflex step lights. It would just flash 3 times then go off.

[samckitt]

How did you find the correct connectors on Mouser's website?  I need one for the connector up by the center rear view mirror to tap into & get power for something.

 

[Derek99]

25 minutes ago, samckitt said:

How did you find the correct connectors on Mouser's website?  I need one for the connector up by the center rear view mirror to tap into & get power for something.

 

What connectors are you talking about?

[samckitt]

4 minutes ago, Derek99 said:

What connectors are you talking about?

The ones that match the GM OEM connectors for the in bed lights?  Did you just eyeball it & find it, or search table somewhere or....?

Thx

[Derek99]

21 minutes ago, samckitt said:

The ones that match the GM OEM connectors for the in bed lights?  Did you just eyeball it & find it, or search table somewhere or....?

Thx

I bought the gen5diy bed light external kit. It came with the connectors. But since the load was too high, I had to add the relay to control my new bed lights.