Jump to content

Aux LED back up lights error

RunGMC19
 Share

Recommended Posts

RunGMC19 Enthusiast

RunGMC19

Posted
Posted

I just installed 2 LED back up lights on my 2019 Sierra 1500 SLT.  I tapped the power off of the cargo lights instead of the reverse lights so I can turn them on and off at will.  When I connected the first light and tested it, it worked fine.  When I connected the second light, they all (bed lights too) flashed 3 times then turned off.  Has anyone discovered a work around for this configuration?

RunGMC19 Enthusiast

RunGMC19

Posted
  • Author
Posted
9 hours ago, gemarsh said:

A 12v relay.

Ok thanks, easy enough, just not sure where I'm going to find a constant 12v power supply at the back bumper.  Run a wire all the way up to the battery?

GETGONE Enthusiast

GETGONE

Posted
Posted

The 12V positive in the trailer harness is hot and you can pull power from there. I had to add a relay because I added 2 2" cube lights on the hitch and brighter LED lights for the Multi Flex tailgate lighting. I have them wired with diodes so they don't backfeed the normal circuits. I have them hooked to the reverse lights as well as the cargo light circuit.

RunGMC19 Enthusiast

RunGMC19

Posted
  • Author
Posted
32 minutes ago, GETGONE said:

The 12V positive in the trailer harness is hot and you can pull power from there. I had to add a relay because I added 2 2" cube lights on the hitch and brighter LED lights for the Multi Flex tailgate lighting. I have them wired with diodes so they don't backfeed the normal circuits. I have them hooked to the reverse lights as well as the cargo light circuit.

Oh, nice.  So you added the diode between the cargo light circuit and the relay trigger, right?  Is that essential, or just for safety sake?

GETGONE Enthusiast

GETGONE

Posted
Posted

I used it because I'm using two different inputs on the same trigger terminal of the relay. I don't want to backfeed the other circuit when one is on. I don't know for sure it would cause an issue, but with how picky the electrical systems are on CAN bus vehicles, better safe than sorry. I pulled the signals from the wiring harness from the tail light to the plug under the bed. I purchased a replacement wire harness so should I ever need to take it to the dealer for any reason, I can pull the added wiring out and put it back to stock.

RunGMC19 Enthusiast

RunGMC19

Posted
  • Author
Posted
2 hours ago, GETGONE said:

I used it because I'm using two different inputs on the same trigger terminal of the relay. I don't want to backfeed the other circuit when one is on. I don't know for sure it would cause an issue, but with how picky the electrical systems are on CAN bus vehicles, better safe than sorry. I pulled the signals from the wiring harness from the tail light to the plug under the bed. I purchased a replacement wire harness so should I ever need to take it to the dealer for any reason, I can pull the added wiring out and put it back to stock.

Oh nice!  Thanks for all the info!  That's a great idea. I think I'm just gonna stick with the cargo light circuit for now so i can control them at will. 

GETGONE Enthusiast

GETGONE

Posted
Posted

I can do both. Control them with the cargo light switch and when I put it in reverse they come on. Also when unlocking at night they come on since the reverse lights come on to light up behind the vehicle.

  • 1 year later...
JH Architect New Member

JH Architect

Posted
Posted

Wade,  would you be willing to share the harness, diodes and relays you used?  Also,  I have heard that adding voltage draw for the LED cube lights can set off error codes.   Have you had any since installing the cube lights?   I want to do the same for my 2019 trail boss but I am afraid of the potential error codes.   

GETGONE Enthusiast

GETGONE

Posted
Posted

This is the write-up I did in another thread on here somewhere. The dealer said my truck had a bunch of body codes when they were scanning it when I got a low oil pressure message several months ago. Those may have been from when I was trying to install an aftermarket remote start with an extended range remote though. I removed the remote start and just left it with the factory one. I don't have anything that will read the body codes in this new truck. I don't get any error codes on the display with my setup though.

 

I added the GM light kit for my multi-flex tailgate as well as swapped the lights to brighter aftermarket LED units. I added some 2"x2" LED cubes I had purchased for my Avalanche but never used. The current draw tripped the BCM and they would blink 3 times then go off. I also hooked the cube lights up to the reverse signal so they come on in reverse and at night when the approach lights turn on when you unlock the truck or lock it and leave. I had added a Curt 5th wheel wiring harness expecting I could get my signals from there for what I was originally wanting to do. I found on here that only the 12V+ wire has signal at all times. I pulled the tail light and looked at the wiring. I have LED bed lights in the corners from factory. I tapped that wire on the passenger side(or could use drivers side) and ran that to the 86 wire on a waterproof relay. I added a 10 amp 1000 volt diode to it so current can't back feed to the bed light circuit. I also tapped the reverse light on the same side, added another 10 amp 1000 volt diode here so current can't back feed the circuit and added it to the 86 wire. There is a harness that plugs in under the bed and connects to the tail lights. I purchased a new harness to keep as a spare in case I ever had electrical issues that required me to take it to the dealer. I can unplug everything I added and return it to stock. 30 wire I connected to the 12V of the Curt 5th wheel harness I added. This plugs in via T to the factory trailer plug. I have the actual 7 wire plug running into the blank in the passenger bed side where the 120V outlet would be if I had that option. 85 wire can be tapped into the trailer harness ground wire or find a suitable ground wire elsewhere on the chassis or tail light harness. 87 connects to your additional lights. I didn't add a fuse to mine since I'm using the 12V+ from the trailer harness and it is already fused. 87a is NOT used and can be removed or taped off. I heat shrunk/electrical taped up connections and then zip tied the relay to the Curt 5th wheel harness along the tail panel of the bed.


For those not wanting to read it all:

Waterproof relay

30 wire - 12V+ from trailer wire circuit

85 wire - 12V- ground to trailer wire ground, taillight ground, or other suitable chassis ground

86 wire - 12V+ input from LED bed lights and/or reverse lights, using a 10 amp 1000 volt diode on each input wire to prevent back feeding trigger circuit

87 wire - 12V+ to your additional lights

87a wire - NOT used and can be removed from relay harness or taped off. Not all relays have this pin/wire

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Newduramaxh*ar
      DTC P2C48 auxiliary cooling pump

      By Newduramaxh*ar · Posted

      I tried tapping it.  This might sound like a dumb question, you should feel vibration or some type of noise when it turns on? Can someone please verify? Thank you all!
    • Chuck FB
      first oil change - 2026 2500HD gas

      By Chuck FB · Posted

      I feel better now for my own view point and actions or lack there of towards the dealership service theme reading your post and others. GM corporate is who offers the two free oil changes on the HD trucks and I bought my truck in Feb of 2025 and those oil change offers run out within 2 years I believe and I highly doubt I will be using either one of them. I had asked if I could officially give those free services to another customer ( a friend ) and they said no, its all a GM corporate thing based on the vehicle in question. What that service advisor did however was go into a little story about how such and such customer was denied engine warranty because he had done his own oil changes because then they are not documented ... you see where that goes and so an employee playing the game of scaring the customer into having the service work done there most certainly triggered my thought process. At a later date I did talk to the person who handles warranty claims at the dealership and she said to be sure to document the oil changes and keep receipts for the oil and filter ( coped the receipts from cases of Mobil oil and case of filters I bought from them ) and the vehicles VIN, the date of service, mileage etc and staple that together as a record I would give them if that was ever needed and I keep my own log book for services for each vehicle as well. Oh and about 8 months after I bought the truck the dealer starts calling me to offer a maintenance service since they haven't seen my vehicle show up on their system ... for the mere fee of 300.00 Canadian to change the oil and rotate the tires and a few other minor checks and I declined the offer, I get the call again a couple of months later for the same thing and she could tell I was not interested and she asked if they should take my name off the call list and I said yes, do that !.    By the way did you happen to keep your factory oil filter to open it up and see the surprises inside as I expect some will show up as per the odd little sliver of metal shaving and particles that the filter does trap along with bits of grey silicone sealer that come off of the inside edge of mating surfaces. I have cut open every filter so far on my truck although few miles but have changed the oil often and the second filter was vastly better with very little of anything, that first filter was the unsettling one as I expected it would be. 
    • OnTheReel
      OCI, not when but why?

      By OnTheReel · Posted

      I get why they do this…but man…not ideal. I only extract on inboard boat engines because the drains are buried and even then I hate it because it’s easy to leave a quart behind with that method.   They should market it as an “oil refresh” not oil change!
    • KARNUT
      OCI, not when but why?

      By KARNUT · Posted

      I only get oil changed where I can watch. Valvoline pulls through the dipstick into a see thru glass. When done they show me the dipstick. About the only way they can mess up is using the wrong oil. But that secret wouldn’t stay secret long. Honda uses TQ wrenches on everything. You can watch through a plate glass window. Discount tires does that with tires. Trust but verify. 
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      I would not argue that with you. It would be pointless to argue against the truth and you speak the truth.    My question and in fact the entire point of this thread is an exploration into the levers of wear which happens no matter how well we maintain our powertrains.    Some of these levers we exert a good deal of influence over which can and do result is lower wear, longer powertrain life. Some others we are sort of stuck with.    An engine is typically done when the ring to bore seal no longer is able to do the job effectively. Normally the first thing to go in a engine otherwise well maintained and adult driven is this seal.    Looking into the means, methods, products and attitudes that influence the rate of wear seems a worthwhile inquiry to me.     

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...