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GMC Sierra All-Terrain X 3rd brake light re-wire after removing stock

kweable
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newdude Senior Enthusiast

newdude

Posted
Posted

 

After reading this, I think I might have been looking for the wrong thing around the UBEC yesterday.

 

So rather than the harness connector, I should be looking for that single (purple) wire that was removed in the UBEC itself, right?

 

I was looking at this connector before:

 

attachicon.gif20161115_115204_2a.jpg

 

 

Yea you have to open the lid on the UBEC. Those two gray handles are the locks that hold it in place. You have to fold those up I think(?) to unlatch the UBEC from the mount. Once you get under that, you should see the wire(s) for the factory CHMSL somewhere there. Remove the roll bar CHMSL replacement wire(s) and install the original(s).

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newdude
newdude

This may help you out:       The key piece of info you need is this:       If you get the UBEC out, there should still be the terminals for the original CHMSL just taped/tied to something.

CobraCmdr
CobraCmdr

Eureka! I got the crazy thing working!   Mad props 15HDriver for the tips and info. The factory wire was left nice and tucked away, wrapped in black tape, inside of the connector in the UBEC as you

kweable
kweable

Thank you! It is a 7" Rough Country lift with 35/12.50/20 Nitto Trail Grappler MT tire. The wheels are Fuels. I don't do any off-road really, mainly just road driving. I have just always lifted my

Posted Images

CobraCmdr Enthusiast

CobraCmdr

Posted
Posted

 

 

Yea you have to open the lid on the UBEC. Those two gray handles are the locks that hold it in place. You have to fold those up I think(?) to unlatch the UBEC from the mount. Once you get under that, you should see the wire(s) for the factory CHMSL somewhere there. Remove the roll bar CHMSL replacement wire(s) and install the original(s).

 

I may try this between now and my next service appt. on the 30th

 

I printed out the section that mentioned the stuff about the UBEC and took it with me to the dealer for my recall appt today.

 

The service guys seemed to understand what needed to be done, but didn't want to make me wait.

 

But then they mentioned something about "if the harness going to the CHMSL isn't right" and "we can always just run a new wire to it"...

 

That got me a bit nervous. Don't want them tearing up the truck running new wire if everything they need to do is right there xD

 

I'll update with pics of the wires, removed UBEC, etc next time I get a chance to work on it. I'm just hoping factory didn't end up cutting the original wires...

newdude Senior Enthusiast

newdude

Posted
Posted

 

I may try this between now and my next service appt. on the 30th

 

I printed out the section that mentioned the stuff about the UBEC and took it with me to the dealer for my recall appt today.

 

The service guys seemed to understand what needed to be done, but didn't want to make me wait.

 

But then they mentioned something about "if the harness going to the CHMSL isn't right" and "we can always just run a new wire to it"...

 

That got me a bit nervous. Don't want them tearing up the truck running new wire if everything they need to do is right there xD

 

I'll update with pics of the wires, removed UBEC, etc next time I get a chance to work on it. I'm just hoping factory didn't end up cutting the original wires...

 

 

The bars get put on by the dealer so I'd be hoping the dealer didn't cut them and just tied them up per the instructions.

CobraCmdr Enthusiast

CobraCmdr

Posted
Posted (edited)

Man...can't thank you enough for all this info. It seems to me that it shouldn't be as hard as their instructions make it out to be. I would think that it would be as simple as group of wires to reconnect, but it seems that it's going to be way more difficult than I imagined. Weird.

 

 

 

 

The bars get put on by the dealer so I'd be hoping the dealer didn't cut them and just tied them up per the instructions.

 

Eureka! I got the crazy thing working! :D

 

Mad props 15HDriver for the tips and info. The factory wire was left nice and tucked away, wrapped in black tape, inside of the connector in the UBEC as you mentioned and we hoped hadn't been cut off LOL

 

I took pics as I made my way down to the wire inside the UBEC to help explain what I found and did.

 

(one thing to keep in mind, I didn't disconnect the battery...some people on other sites said to do so, others didn't.)

 

Once I was able to get the UBEC up and partly out of the way, I found connector X3 and saw the wire from the sport bar brake light going into it. I opened up the connector to expose the wires:

 

Found the factory wire all nice and taped up!

 

post-165182-0-17608800-1479416781_thumb.jpg

 

Next thing I did was to carefully pull the black tape off, making sure not to damage the wire

 

post-165182-0-72728700-1479416802_thumb.jpg

 

Then, turning the connector X3 around, I found the sport bar brake light wire. I marked the port, just in case I forgot which one it was in.

 

post-165182-0-71872500-1479415494_thumb.jpg

 

Then, I turned the connector back around and removed the blue clip to expose the latches that keep each of the wires in place. This part was a bit of a pain as the clip is pretty thin, and I didn't want it to break, so it just took some time to ease out of the connector. Once the clip was off, I used a probe tool to push down the latch that held the wire for the sport bar brake light and then slowly pulled the wire out.

 

post-165182-0-49979200-1479416013_thumb.jpg

 

After that, I inserted the factory wire into the port where the sport bar brake light wire was and then reassembled everything, making sure everything was free of debris and snug.

 

I used black tape to wrap the sport bar connector and just taped it off in case I, or someone else ever wants to reinstall the sport bar again :D

 

kweable, it's totally doable yourself if you have some patience and a few tools. Really, the only part that was a bit crazy was taking off the blue clip on the X3 connector.

 

Hope the pics helped!

 

EDIT: Worth noting that when starting the truck after the EBEC is disconnected/reconnected, there were several things that popped up on the info center: outside temp alert (noticed the displayed temp on the nav screen showed 32F, when it is was actually 73F here today) and something about Driver 2.

 

Both of these alerts cleared and the temp corrected itself after about 10 mins of driving. I'm guessing stuff needed to resync/calibrate after the EBEC was disconnected for so long.

 

Anyways, just a headsup :D

post-165182-0-71872500-1479415494_thumb.jpg

post-165182-0-49979200-1479416013_thumb.jpg

post-165182-0-17608800-1479416781_thumb.jpg

post-165182-0-72728700-1479416802_thumb.jpg

post-165182-0-71872500-1479415494_thumb.jpg

post-165182-0-49979200-1479416013_thumb.jpg

post-165182-0-17608800-1479416781_thumb.jpg

post-165182-0-72728700-1479416802_thumb.jpg

post-165182-0-71872500-1479415494_thumb.jpg

post-165182-0-49979200-1479416013_thumb.jpg

post-165182-0-17608800-1479416781_thumb.jpg

post-165182-0-72728700-1479416802_thumb.jpg

Edited by CobraCmdr
  • Like 1
kweable Enthusiast

kweable

Posted
  • Author
Posted

Nice! Can't wait until I have some time to give it a stab. Thanks again for all the info...HUGE help!!!

  • 3 months later...
craig944 Enthusiast

craig944

Posted
Posted

Leaning towards ordering the x edition but removing the sport bar.

Maybe I missed it but what color was the wire from the sport bar that u removed to replace with the taped off purple/grey cab brake wire.?

 

Thanks

Kovacjr Enthusiast

Kovacjr

Posted
Posted

I too have the AT X a 2016 and put on a BAK Revolver X2. Wanted to remove the roll bar too, dealer had no clue. Poked around saw that the harness is loomed into the main and it would be left there. Ended up trimming out the rails to fit around the bar and its still there. Maybe someday Ill remove but then I also need to replace the rails. I also then needed to replace the upper bed plastic as the punched out the front holes for the mounting.

Good to know now that it can be rewired with ease compares to running new ones up there.

Rock1500 Senior Enthusiast

Rock1500

Posted
Posted

Has anyone taken off the roll bar of a All-Terrain X and re-wired the 3rd brake light???

 

Love the truck, didn't like the roll bar, want my 3rd brake light to work

Thanks!!!

 

Love the stance. What lift / tires / rims do you have setup? Trying to figure out the height.

 

Sent from my Pixel XL using Tapatalk

kweable Enthusiast

kweable

Posted
  • Author
Posted

Love the stance. What lift / tires / rims do you have setup? Trying to figure out the height.

 

Sent from my Pixel XL using Tapatalk

 

Thank you! It is a 7" Rough Country lift with 35/12.50/20 Nitto Trail Grappler MT tire. The wheels are Fuels. I don't do any off-road really, mainly just road driving. I have just always lifted my trucks cause I like the looks of them. I am real happy with it. I only had to do a very slight trim to the air dam under the front bumper and have little to no rubbing. Truck rides great and I love the look. It definitely sits high enough. I don't go into any car washes, drive throughs, or parking garages that aren't at least 7'3". The only other thing I'm going to do is add some Bilstein 1500 adjustable ride height shocks down the road.

Thanks again.

  • Like 1
  • 4 weeks later...
GlenS Enthusiast

GlenS

Posted
Posted

Anyone know where the Chmsl wire is on the rear of the truck near the spare tire? I need to hook my 3 brake light up from my truck cap? Stumbled across this post and has some great tips.

Thomcat Senior Enthusiast

Thomcat

Posted
Posted

 

 

 

Eureka! I got the crazy thing working! :D

 

Mad props 15HDriver for the tips and info. The factory wire was left nice and tucked away, wrapped in black tape, inside of the connector in the UBEC as you mentioned and we hoped hadn't been cut off LOL

 

I took pics as I made my way down to the wire inside the UBEC to help explain what I found and did.

 

(one thing to keep in mind, I didn't disconnect the battery...some people on other sites said to do so, others didn't.)

 

Once I was able to get the UBEC up and partly out of the way, I found connector X3 and saw the wire from the sport bar brake light going into it. I opened up the connector to expose the wires:

 

Found the factory wire all nice and taped up!

 

attachicon.gif20161117_123732_aa.jpg

 

Next thing I did was to carefully pull the black tape off, making sure not to damage the wire

 

attachicon.gif20161117_123924_aa.jpg

 

Then, turning the connector X3 around, I found the sport bar brake light wire. I marked the port, just in case I forgot which one it was in.

 

attachicon.gif20161117_124100_a.jpg

 

Then, I turned the connector back around and removed the blue clip to expose the latches that keep each of the wires in place. This part was a bit of a pain as the clip is pretty thin, and I didn't want it to break, so it just took some time to ease out of the connector. Once the clip was off, I used a probe tool to push down the latch that held the wire for the sport bar brake light and then slowly pulled the wire out.

 

attachicon.gif20161117_133622_a.jpg

 

After that, I inserted the factory wire into the port where the sport bar brake light wire was and then reassembled everything, making sure everything was free of debris and snug.

 

I used black tape to wrap the sport bar connector and just taped it off in case I, or someone else ever wants to reinstall the sport bar again :D

 

kweable, it's totally doable yourself if you have some patience and a few tools. Really, the only part that was a bit crazy was taking off the blue clip on the X3 connector.

 

Hope the pics helped!

 

EDIT: Worth noting that when starting the truck after the EBEC is disconnected/reconnected, there were several things that popped up on the info center: outside temp alert (noticed the displayed temp on the nav screen showed 32F, when it is was actually 73F here today) and something about Driver 2.

 

Both of these alerts cleared and the temp corrected itself after about 10 mins of driving. I'm guessing stuff needed to resync/calibrate after the EBEC was disconnected for so long.

 

Anyways, just a headsup :D

Wish I had seen this post sooner. Following GMs instructions for connecting the CMHSL on a new sportsbar and disabling the factory one is a colossal waste of time, requires taking apart and changing pins in harnesses, etc.....and not easily reversible without wasting another two ours and resplicing wires and praying all of the 200+ pins reconnect properly.

 

All you have to do is to connect the ground wire somewhere, but instead of a complicated slice for the positive lead into the existing harness.....connect the positive to a fuse tap containing space for he existing fuse and a secondary fuse for the new positive wire. I chose to leave the slot for the existing fuse blank so the original CMHSL is not powered but placing the fuse in the secondary slot in the tap feeding only the new CMHSL positive wire. Simply remove the CMHSL fuse from the fusebox and replace with the tap....all done in under five minutes including the time to file a slot in the fusebox for the wire to exit. To restore the original CMHSL operation insert a fuse in the other tap., or remove the tap and place the fuse i the original fusebox slot.

post-156616-0-90107700-1491955585_thumb.jpg

post-156616-0-46206400-1491955599_thumb.jpg

post-156616-0-90107700-1491955585_thumb.jpg

post-156616-0-46206400-1491955599_thumb.jpg

post-156616-0-90107700-1491955585_thumb.jpg

post-156616-0-46206400-1491955599_thumb.jpg

post-156616-0-90107700-1491955585_thumb.jpg

post-156616-0-46206400-1491955599_thumb.jpg

  • Like 1
  • 4 weeks later...
Zrock87 Enthusiast

Zrock87

Posted
Posted

 

 

 

Eureka! I got the crazy thing working! :D

 

Mad props 15HDriver for the tips and info. The factory wire was left nice and tucked away, wrapped in black tape, inside of the connector in the UBEC as you mentioned and we hoped hadn't been cut off LOL

 

I took pics as I made my way down to the wire inside the UBEC to help explain what I found and did.

 

(one thing to keep in mind, I didn't disconnect the battery...some people on other sites said to do so, others didn't.)

 

Once I was able to get the UBEC up and partly out of the way, I found connector X3 and saw the wire from the sport bar brake light going into it. I opened up the connector to expose the wires:

 

Found the factory wire all nice and taped up!

 

attachicon.gif20161117_123732_aa.jpg

 

Next thing I did was to carefully pull the black tape off, making sure not to damage the wire

 

attachicon.gif20161117_123924_aa.jpg

 

Then, turning the connector X3 around, I found the sport bar brake light wire. I marked the port, just in case I forgot which one it was in.

 

attachicon.gif20161117_124100_a.jpg

 

Then, I turned the connector back around and removed the blue clip to expose the latches that keep each of the wires in place. This part was a bit of a pain as the clip is pretty thin, and I didn't want it to break, so it just took some time to ease out of the connector. Once the clip was off, I used a probe tool to push down the latch that held the wire for the sport bar brake light and then slowly pulled the wire out.

 

attachicon.gif20161117_133622_a.jpg

 

After that, I inserted the factory wire into the port where the sport bar brake light wire was and then reassembled everything, making sure everything was free of debris and snug.

 

I used black tape to wrap the sport bar connector and just taped it off in case I, or someone else ever wants to reinstall the sport bar again :D

 

kweable, it's totally doable yourself if you have some patience and a few tools. Really, the only part that was a bit crazy was taking off the blue clip on the X3 connector.

 

Hope the pics helped!

 

EDIT: Worth noting that when starting the truck after the EBEC is disconnected/reconnected, there were several things that popped up on the info center: outside temp alert (noticed the displayed temp on the nav screen showed 32F, when it is was actually 73F here today) and something about Driver 2.

 

Both of these alerts cleared and the temp corrected itself after about 10 mins of driving. I'm guessing stuff needed to resync/calibrate after the EBEC was disconnected for so long.

 

Anyways, just a headsup :D

 

 

 

THIS WAS AN AMAZING POST! TY!! YOU MADE LIFE SO MUCH EASIER!

  • 3 months later...
johnnyg123 Enthusiast

johnnyg123

Posted
Posted

would like to bump this to the top. i bought a 2017 2500 hd all terrain package. would like to know how difficult it would be to remove the sport bar so so i can have it painted to match the truck ? is there a plug for the lights and where would it be located? i realize ill be without the 3rd brake light for a few days while its being done. thanks

Michael Schimborski Enthusiast

Michael Schimborski

Posted
Posted

would like to bump this to the top. i bought a 2017 2500 hd all terrain package. would like to know how difficult it would be to remove the sport bar so so i can have it painted to match the truck ? is there a plug for the lights and where would it be located? i realize ill be without the 3rd brake light for a few days while its being done. thanks

The plug is under the driver side right below the stake hole next to the rear glass. Unbolt the sport bar and slide down the bed and you and wiggle the wire to see it from underneath. It's real easy. There's a zip tie you need to cut to allow it to be pulled out. Getting it back down is the hard part. A metal hanger works for that tho

 

 

Sent from my iPhone using Tapatalk

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