How to Wire a Leer Truck Topper Third Brake Light (CHMSL) and Automatic Lock and Unlock Functions

[@cackerson10]

Great video, they are hard to come by. Wish they made an easier connection at the power blocks under the dash so you didn't have to splice. The Manufacturers should know by now a lot of people buy caps. Thanks again!

[@AJSWoodworks]

Thank you! I completely agree. It hurt me a little to splice into the wires.

[@NoNeckadventures]

Thank you for this video. Helped me wire mine correctly.

[@bradschmidt5162]

Do you know which BCM block, and the PIN number for a 12 volt source for the dome light? Thanks!

[@dustintownsend7810]

Thank you Great video. When I sodderr id get the wire a little hotter so that it pulls the sodder into the wire

[@AJSWoodworks]

My soldering iron would not get any hotter unfortunately. I think it might be time for a new one.

[@DougWestfall]

excellent video, I'll be doing mine soon, Thanks!

[@jakekelley24]

For those who want the dome lights to work, and 12v source as well just continue the red wire to the battery along the frame and add an inline fuse. That will get you dome lights. You also need to add a jumper wire on the incoming fuse box plug on the shell on the POS6 connector #3 (dome) and #6 (aux power) for the aux power.

[@JerryTurner]

I was able to get mine going with this setup, however I have some concerns about the draw direct on the battery without a timer, or switch, if it gets left on I would worry that it is going to leave me stranded.

[@timjohnson1042]

any reason why you did not tap the brake wires near the brake light? Also, can you tap the lock / unlock wires at the tailgate?

[@AJSWoodworks]

It will not connect to the chmsl, which will cause the brake lights to flash when the brakes are applied rather than staying lit up constantly. It would also result in the brake light flashing with the turn signal. It must be tapped into under the dash.

[@dddbbb4731]

Where did you get the info. Just wandering because ARE shells say do the white wire blue stripe on the brown connector for chmsl

[@AJSWoodworks]

I got it from the LEER papers and online research. It works perfectly.

[@dddbbb4731]

Gotcha the a.r.e. papers say x5 white blue and it works. Lol must be 2 good spots.

[@MrAlbrimm]

Solder is attracted to heat. Place your iron on onside of the conductor and solder on the opposite side. Super easy

[@ajw5743]

Anyone know where I can get a wiring kit? I purchased mine used, and so I need to wire it in. Many of the kits I see only have the plug with the red/ red white/ ground. They don't come with the cables for the lock/unlock.

[@robbyvaughn4450]

Great video I’ve also got a leer cap. I’ve not done the lock and unlock yet. Mine is a 2023 what year is yours ? Just wanted to make sure the wire colors are the same for this. Thanks

[@AJSWoodworks]

It’s a 2021

[@roberta4989]

Your interface into the TAG fuse box does not match the instruction sheet from TAG. The sheet from TAG shows the Green wire between the Red and Red/White stripe wires on the connector and the Blue wire between the Black and Red/Black wires. The wires that you interfaced on the under dash connector - Brown/Yellow to the Blue wire and the Green wire to the Gray wire match the instruction. Yours worked, I am doing it like you, switching the Green and Blue wires at the TAG fuse box. Hope it works. If so THANKS!

[@B1NT1]

Just what I was looking for, thanks a bunch! I can't get my CHMSL to power on, does the Red with White stripe power and the black ground for the CHMSL? Thanks!

[@AJSWoodworks]

Yes, the red and white wire is power and black is ground. Check the arrangement of them

[@gregorystewart9523]

Your video was very helpful, but I have a 2024 Silverado HD. The BCM has a different layout and different plug colors than yours and I’m wondering if the color of the wires also changed. Do you have any suggestions on where to find information on which wires to tie into? I’m having trouble finding any information for a 2024.

[@AJSWoodworks]

Unfortunately it’s difficult to find that info. I searched Silverado mechanical bulletins and technical bulletins for the info.

[@robbyvaughn4450]

Was you able to find what wires to tap into for your 24 ?

[@gregorystewart9523]

@@robbyvaughn4450 Yes. Under the driver side kick panel there are several wire looms. Find the wire loom that goes to your rear door pillar. Inside that loom will be a White wire for 'door lock' and a Blue/Yellow wire for 'door unlock'. I soldered to those two wires, and it works great!

[@rickmcgaver4698]

Have you had any luck finding the correct wire and location. I have a 2024 GMC Sierra and it is not like this video.

[@gregorystewart9523]

@@rickmcgaver4698 For the 2024 Silverado under the driver side kick panel there are several wire looms (assuming the Sierra would be the same). Find the wire loom that goes to your rear door pillar. Inside that loom will be a White wire for 'door lock' and a Blue/Yellow wire for 'door unlock'. I soldered to those two wires, and it works great!

[@garthaegerter2704]

How’d you find this information? Cause I have a 2015 Silverado and I want to figure it for my truck.

[@AJSWoodworks]

Some info came with the topper, I also spent hours scoring the internet and looking at wiring diagrams for the specific year.

[@josephdewuhan]

I got a 2024 model. Is the CHMSL wire is the same as this pink with white tripe wire as in this video?

[@AJSWoodworks]

@@josephdewuhan I’m not sure, if I remember correctly it is different

[@robbyvaughn4450]

What color wires will it be on 2023 ? Also it looks like I’ve got 2 lines of connectors . I see just one line on yours where you are counting to what plug to unplug

[@AJSWoodworks]

@@robbyvaughn4450 I’m not sure what color it would be on a 2023, I wish they would keep it the same between years. Unfortunately, there may be a different way to wire it to your specific 2023. It took me hours to figure out how to wire mine.

[@joshuaschilling5691]

I have the same kit but I didn't get the additional 3 wires, did yours come with a total of 6?

[@AJSWoodworks]

Mine came with the green and blue wires, and the black/red/and red and white wires. The extra black wire I purchased.

[@AJSWoodworks]

So only 5 total

[@Juicesquaredchevy]

We’re would I find the computer pin out identification for earier year Silverado models?

[@AJSWoodworks]

There are manuals on the internet regarding the pin locations for basically all year models. No great single website unfortunately.

[@Juicesquaredchevy]

@@AJSWoodworks part numbers for chassis side harness? Can’t seem to find lock and unlock cables

[@caseyzilinek6427]

What would cause the lock to not work with the unlocking of the truck? Everything else brake light and dome light are working fine.

[@AJSWoodworks]

Does it unlock or lock at all? You should hear a click from the locking mechanism. If you don’t, the wiring is either not spliced correctly or the wires are not oriented properly in the connection.

[@caseyzilinek6427]

Thanks for the reply! It locks with the truck but doesn’t unlock. I actually hear it click when it locks and unlocks. I had to get a new lock this year after my old one broke loose from the glass. It worked fine before they replaced it. I tried taking the blue and green wires out and switching them as well.

[@AJSWoodworks]

@@caseyzilinek6427 Hmmm, weird. Maybe a bad connection somewhere, potentially at the lock.

[@Lymerock]

looking at the wiring diagram, seems you have the blue and green reversed in the plug. did you confuse the wires at the bcm/ get the lock unlock backwards? I plan to add that feature soon. also for anyone that cares there is a Tag interface harness that works with 2019+ gmc/chevy and is plug and play at the rear bumper. Tag interface harness kit # C90-917

[@AJSWoodworks]

I had it backwards initially, but what you see towards the end of the video is the correct arrangement.

[@MikeWood1]

@Lymerock can you confirm part number for the kit you mentioned? I can only find C90-907

[@Lymerock]

@@MikeWood1 that was the PN from the paperwork with the kit. It was all plug and play under the truck. it connected to both tail light harnesses. The PN you gave is not what I used. I had my leer dealer source the kit, its an upgraded version for facelift and newer trucks.

[@ajw5743]

What do you mean? It looks like at the start of the video, he has the correct arrangement according to the wiring diagram.

[@ajw5743]

Anyone know the relevant wire locations for a 2018 f150 xlt? It is diffedent than what is in this video..

[@limpy88]

Thanks for posting.

[@rebelmechanic7392]

I have the tag module but I don't have the bottom pigtail where can I get the bottom pigtail I can't find out online ?

[@AJSWoodworks]

It came with my topper, you might have some luck at truck and trailer or from TAG.

[@AJSWoodworks]

truckoutfittersplus.com/truck_topper_parts/Topper-Wiring-Harness/Topper-Fuse-Box-Wire-Harness-only.html

[@wack1305]

Thank you!

[@georgewastaken]

They’ve been manufacturing these fiber shells for decades, some truck dealers will even sell them directly to you. With that in mind, there not being a factory included pigtail at tailgate to provide all the necessary signals to make these work is just bonkers to me.

[@franktartan6808]

Helpful video. Man you need to learn to solder! There are plenty videos and it is not hard to do., but you really to learn some technique. Don’t mean to be critical.

[@AJSWoodworks]

It’s either an issue with my soldering iron not heating up high enough, or the soldering material that I have is not the correct type for my soldering iron. I’ve soldered before with different soldering material and had no issue. That’s how I installed the head unit in my car. The solder would slightly melt and would fall off the wire, because my soldering iron was not maintaining its heat.

[@franktartan6808]

@@AJSWoodworks I had an iron that did not get hot enough. I heated it with the propane torch.

[@asfltcwby]

​@@AJSWoodworksthats not correct. The reason you're having trouble is because you're applying heat incorrectly. Apply heat directly to the wire and the solder will wick into the wire. What you're doing is called a cold solder joint and provides no conductivity and minimal structural support. I'm IPC-610 certified, just trying to hell you get better

[@AJSWoodworks]

@@asfltcwby I applied heat to the wire directly as well with no success.

[@xtxdrip]

My 3rd brake light stopped working and idk why or how

[@AJSWoodworks]

I would check your wires, it may be that you don’t have a good connection somewhere.

[@losmentadosderichmond689]

Where do you get all cables

[@AJSWoodworks]

@@losmentadosderichmond689 I bought the extra wire from autozone.

[@horseman3266]

You can also tie into your 7 way plug wires under the spare tire

[@Jasun78]

Just hook it to your break light on the truck

[@AJSWoodworks]

Unfortunately, that will cause the third brake light to flash when you apply the brakes. It will also cause the third brake light to flash when you apply the turn signal.

[@greedyg76]

Depends on the layout of the lights on your truck. If you have separate brake & turn signal bulbs in the taillight it should work fine

[@crispychicken2743]

To complicated , just go to the brake light harnesses.

[@AJSWoodworks]

@@crispychicken2743 Yeah, and watch your 3rd brake light flash every time you turn on your turn signal.

[@johnmcquarrie5041]

Ditch those garbage Ranchos, best thing I did was replace the stock struts and shocks in my Silverado

[@AJSWoodworks]

I will once they need replacing. Then they’ll get an upgrade!

[@johnmcquarrie5041]

@@AJSWoodworks I went with Eibach and it feels like a 'truck' now. Was pretty wallowy on the stock setup. Thanks for the video