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I fixed my other issues with the LF ABS wiring, now I have "trailer not connected" that comes up. When you manually activate the trailer brakes by hand on the dash, no brakes engage (same when you use your foot on the brakes) the display comes on, but stays black and grey, does not come on in color like it should when working correctly. I tried two different trailers with electric brake, same result, not working. It is an intermittent issue, but mostly does not work. I went through the wiring on one of my trailers completely, no issues. The second trailer is brand new, same issue. It has to be in the truck somehow, what makes this system engage? I was told it sees a load on the circuit somehow, so it appears to not see it. Any ideas?

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37 minutes ago, Hillwood said:

Let's start with year  and  model.

His sig says 2017, LTZ-Z71, Crew Cab, Short Box, 1500, 6.2, 8 Speed, MIDNIGHT

 

I've seen others on here with this same issue. Get some dielectric grease in the connector.

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Posted (edited)

Correct, truck specs are in the sig, and no, no corrosion whatsoever, I always coat the plug and receiver with dielectric grease. Thank you for responding...

Edited by 6.2Midnight

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How does the truck know if the trailer is plugged in?

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I believe from the brake wire pin the usually blue wire is the wire that controls it.


Sent from my iPhone using Tapatalk

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Posted (edited)

If it were just a poor connection, I believe it would say "Check Trailer Wiring" (according to the manual). The upfitter manual addresses the trailer brake controls and all starting on page 126.

 

https://www.gmupfitter.com/files/media/photo/761/Sierra_Silverado_Electrical_Body_Builders_Manual_Service_Manual_2017_en_US.pdf

 

image.thumb.png.be16291b4439bbf00c3238905b3069b7.png

Edited by NCPGMC

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Thanks for the upfitter info., I have been reading a lot on this issue. All things given, I do not see the trailer being the issue at his point. I have narrowed it down to these two options;

1) Plug from trailer not going in far enough to receiver of truck

2) Go through the wiring on the receiver of the truck

 

From what I have read, the truck is very sensitive to voltage, even if it's a little low, it will throw the code.

 

I have not tried the "turn off the truck, then plug in the trailer, things should work" approach, but will try it, what can it hurt?

 

It will be a day or so before I can get to it, just had shoulder surgery yesterday from my last run in AFG. Currently the nerve block is still working, and my whole are is still paralyzed,.

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I sorry to hear about your health.. I hope you are better soon. 

I would suggest pulling the chassis (C) codes.. There should be codes if there is a fault in the truck wiring.. This would give you a starting point for diagnosing. 

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