GMC Truck Forum banner

1 - 20 of 51 Posts

·
Registered
Joined
·
111 Posts
Discussion Starter #1
I have s 2015 2500HD LTZ manufactured 8/14. I had some DQS tow mirrors installed at the dealership. I had my DL3 mirrors removed which had all the functions. The two new functions on the tow mirrors are those white reverse lights and the amber running lights.

Had the dealer install them, two new door harnesses, and the RZY jumper harness because mine is a early 2015.

All the lights work on the mirrors however when I put my truck in reverse the white reverse lights go off. They only stay on in park or neutral which makes no sense. I thought they were to be used to assist at night time.

Needless to say I’m taking the truck back to the dealership. But I was wondering in the meantime, do any of you guys have these tow mirrors on a 2015 or earlier truck? Just wondering what they could’ve done to where the white mirror lights do not stay on when the transmission is in reverse.
 

·
This place sucks dicks
Joined
·
4,938 Posts
Pretty sure the intention is for those lights to come on when you hit the bed light switch. The bed lights also go off when you put it in any gear.
 

·
professional grade
Joined
·
4,086 Posts
Like Barrffff said, they function with cargo light on but they do stay on in reverse. At least I believe that’s the case with my HD
 

·
Registered
Joined
·
111 Posts
Discussion Starter #4
Pretty sure the intention is for those lights to come on when you hit the bed light switch. The bed lights also go off when you put it in any gear.
Yeah that’s how the cargo lights above the rear window work. However, I’ve looked on YouTube and have been googling a lot and it appears these are supposed to be reverse assist lights to help when backing up/hooking a trailer up at night.

Not sure why you would want lights on the side of your truck if you’re in park. It’s very convoluted that’s for sure my heads about to explode.
 

·
Registered
Joined
·
111 Posts
Discussion Starter #5
Like Barrffff said, they function with cargo light on but they do stay on in reverse. At least I believe that’s the case with my HD
Yeah that was my impression. With the truck in park you push the cargo light button underneath the HVAC controls on the dash. That illuminates the mirror white LEDs as well as your bed cargo lights. Then when you shift into reverse the bed cargo light to go off but the white mirror lights stay on.

Kenny it would be a huge help man… If you get a chance in the next hour or two would you be able to confirm that those mirror lights stay on while in reverse?
 

·
professional grade
Joined
·
4,086 Posts
Yeah that was my impression. With the truck in park you push the cargo light button underneath the HVAC controls on the dash. That illuminates the mirror white LEDs as well as your bed cargo lights. Then when you shift into reverse the bed cargo light to go off but the white mirror lights stay on.

Kenny it would be a huge help man… If you get a chance in the next hour or two would you be able to confirm that those mirror lights stay on while in reverse?
Won’t be home till 6pm to verify
 

·
This place sucks dicks
Joined
·
4,938 Posts
I read somewheres you needed a jumper under the dash on one of the BCMs to get them to stay on in reverse. But idk.
 

·
Registered
Joined
·
111 Posts
Discussion Starter #9
I read somewheres you needed a jumper under the dash on one of the BCMs to get them to stay on in reverse. But idk.
Yes that is exactly right. I actually purchased that harness and explain to the dealership that my truck needed that being an early 2015. It’s the RZY camper harness. The GM part number is 23387133.

I should not have to be having this problem. so I’m not sure if the technician made one small mistake that is causing this. I just hope he can get it figured out.
 

·
Unofficial VP of GMFS
Joined
·
3,326 Posts
There is a way to make them stay on constantly local guy runs his at night but don’t know how he does it
 

·
Registered
Joined
·
111 Posts
Discussion Starter #11
There is a way to make them stay on constantly local guy runs his at night but don’t know how he does it
Yeah not really interested in that. I really want to use these at night while backing up a dark driveway or hooking a trailer up. I heard they help pretty good.
 

·
Registered
Joined
·
111 Posts
Discussion Starter #13
The diode is $3 for a pack of 10.


Sent from my iPhone using Tapatalk
Yeah I’ve seen how cheep they are. Wonder where you can get them local? I see them on Amazon.

So even though I can’t get them to stay on in reverse using the cargo button, doing that diode mod would make them work in reverse? Like just come on every time in reverse without hitting the cargo button?
 

·
Super Moderator
Joined
·
5,854 Posts
Yes. It will make your cargo and bed lights come on in reverse as well. For extra light.

It will also make all those lights come on when you unlock your truck.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
111 Posts
Discussion Starter #17
Yes. It will make your cargo and bed lights come on in reverse as well. For extra light.

It will also make all those lights come on when you unlock your truck.


Sent from my iPhone using Tapatalk
Ok man, thanks for the help. Do you have your mirrors set up like that? Or just know this from experience? Just wondering since I received lots of input on this and it’s varied widely.
 

·
Super Moderator
Joined
·
5,854 Posts
I don’t. I just know the diode will make all lights turn on anytime the reverse lights kick on. I had forgot about the mod and actually just did it to my 2017 last night.


Sent from my iPhone using Tapatalk
 

·
Super Moderator
Joined
·
5,600 Posts
The mirror lights are a joke and more of an annoyance backing up then helpful. Also they dont come on in reverse, at least not in dads 17.

Sent from my SM-G960U using Tapatalk
 

·
This place sucks dicks
Joined
·
4,938 Posts
The mirror lights are a joke and more of an annoyance backing up then helpful. Also they dont come on in reverse, at least not in dads 17.

Sent from my SM-G960U using Tapatalk
Thats what I said. Needed a mod to do that.
 
1 - 20 of 51 Posts
Top