What Triggers "Check Trailer Wiring" DIC Message

[Lance S]

On 8/24/2023 at 2:20 PM, Gator888 said:

Possibly related to a power back feed, do you have solar panels on the trailer? Check out this thread: 

This is the exact issue!!  I found someone who posted they thought it was something to do with the battery & solar panels.  On our last trip, the message never happened for 4.5 hours.  After camping all weekend with shore power, we pulled out and started driving home.  Within an hour, the trailer disconnect message started up (as a side note, I have 2 -200W solar panels and it was full sun at the time).  I pulled over and put the battery in to disconnect using the switch and it IMMEDIATELY stopped.  For the next 3.5 hours, it was flawless.  THANK YOU very much for posting this!  I'll send this to the camper dealership tomorrow.

 

Edited August 29, 2023 by Lance S

[Garry S]

Brand new 2024 Silverado 2500HD & brand new Pinnacle 5th wheel with same issue. Looking for suggestions of where to begin diag. Thanks.

[UWSkier]

9 hours ago, Garry S said:

Brand new 2024 Silverado 2500HD & brand new Pinnacle 5th wheel with same issue. Looking for suggestions of where to begin diag. Thanks.

Known issue.  GM has a fix.  Ask your service advisor to check GM bulletin 23-NA-149

[Lisa Daiek]

I have had this ongoing issue with my 2020 Silverado 1500. I have not only had  the Dealership check it out at least 3x (with and without the trailer attached), and additionally, took the Trailer to Gen.RV to have it thoroughly checked out 2x. I also had an independent mechanic check it out (no results other than, "take it to the Dealership") and a retired auto electrician who happened to be at the same campground as me and heard my frustration being voiced. Ultimately, this seasoned engineer spent two full days putzing on my truck/trailer combo and tested everything. He was able to print a very thorough GM document (not sure where he found it.. didn't look like just a plain internet search), which demonstrated that GM CLEARLY knows this has been an issue with MANY of their trucks! I have now officially opened a complaint case with GM. I explained to them that THEY know there is a problem and when my electric brakes give out sporadically, leaving no warning, there WILL eventually be an accident and THEY will be held liable. This is very frustrating for MANY of us. Please, open a case with GM so that they do something.. a recall.. anything. This is so dangerous!

[Lisa Daiek]

What do we all have to do to get this problem on the SAFETY RECALL list? It's a matter of time before somebody gets seriously injured or worse. 

[Zot W]

Went thru this list of (23 NA 149 & found lots of engines except 6.6L Gas.

Maybe I missed it, but the fixes were eliminating wear & grounding of wiring in the engine compartment. Couldn't find similar conditions along the wiring to or from the RV plug or controller areas.

Ours like those getting the DIC check trailer wiring message etc. Varies when & where. Metering the plug & socket shows various conditions. One regular "cause" but not always, is slowing coming into a small town. The 1st-3rd braking will pop up the DIC warnings. Then jumping out & chasing that rabbit (shaking the, plug, repluging, measuring voltage in jbox, any touching the circuits) causes it to go away or sometimes come on. Never long enough to track it down.

Replaced the plug, cleaned everything. Started about 2k miles ago & fails mostly going down a grade. But also happens going up hill or on the flat @ any speed

2020 denali, & 2020 keystone cougar bumper pull.

47,k on Denali & 60k on trailer.

[GMCJeff]

I was having the trailer disconnected  message frequently on my 2020 sierra. Noticed that during a trailer light test, that a relay was clicking near the hitch on the truck. It was coinciding with the disconnected notification.  So I set out to check exactly when the disconnect notification occurred in conjunction with every ltg condition.

I found that when the tail lights were on, either turn signal caused the disconnect notification.  

( Turn signal denergizes tail lamp during the flash) 

So upon googling I came across a GM bulletin that showed the trailer control module uses the tail lamp circuit to monitor weather a trailer is present! It has a high enough wattage threshold that may or may not be met by low draw LED bulbs. My camper is a pre LED era  model, and when I first bought it had upgraded all lamps to improve efficiency and eliminate the heat. 

So I swapped out the 1157 tail bulbs to incandescent originals and Wallah....the issue is resolved. 

Attached below is the GM info. 

I hope this helps some folks. 

GM needs to fix this issue. Obviously the engineers set the trailer monitor wattage threshold too high to allow for the lighter LED wattage.  It causes a potentially dangerous condition as it disables trailer brakes and lights when it occurs. 

https://static.nhtsa.gov/odi/tsbs/2022/MC-10208985-9999.pdf

[GMCJeff]

I was having the trailer disconnected  message frequently on my 2020 sierra. Noticed that during a trailer light test, that a relay was clicking near the hitch on the truck. It was coinciding with the disconnected notification.  So I set out to check exactly when the disconnect notification occurred in conjunction with every ltg condition.

I found that when the tail lights were on, either turn signal caused the disconnect notification.  

( Turn signal denergizes tail lamp during the flash) 

So upon googling I came across a GM bulletin that showed the trailer control module uses the tail lamp circuit to monitor weather a trailer is present! It has a high enough wattage threshold that may or may not be met by low draw LED bulbs. My camper is a pre LED era  model, and when I first bought it had upgraded all lamps to improve efficiency and eliminate the heat. 

So I swapped out the 1157 tail bulbs to incandescent originals and Wallah....the issue is resolved. 

Attached below is the GM info. 

I hope this helps some folks. 

GM needs to fix this issue. Obviously the engineers set the trailer monitor wattage threshold too high to allow for the lighter LED wattage.  It causes a potentially dangerous condition as it disables trailer brakes and lights when it occurs. 

https://static.nhtsa.gov/odi/tsbs/2022/MC-10208985-9999.pdf

[Gespringer1]

2016 Denahli HD, puling 27' 5th wheel, or a car hauler. This trip started out at 72 degrees. Three hours later it's 78, and check trailer wiring message repeats, sometimes every 3 seconds. Had the message once as I was unhooked, about to park it for the night. No longer blame the 5th wheel, but have no clue!

[gmen]

This module 381-7075 from Hydrastar fixed my issue. Talked to the guy at the Hydrastar and he said they have had a ton of success with them. Super easy to install, took 5 minutes.