trailer harness wiring question [Archive]

DAB

07-10-2019, 3:59pm

this gang has to know the answer:

have a 2013 chevy silverado 2500hd truck, it came with the Heavy Duty Trailer Wiring Harness Package, so I have an installed harness and electric brake controller on the lower dash board. the manual says it's all good to go...except that the wires for the Battery Feed (Red) and for the Trailer Brake (Dark Blue) are not connected to the fuse box, but the fuses are installed (page 9-96 of owner's manual).

i'm getting a trailer shortly, with electric brakes, and i need this mess to work properly first time out.

do i need to have the dealer do the final wiring connections, or is that something I could do? tried searching youtube, but didn't find any videos with this covered.

Black94lt1

07-10-2019, 4:19pm

I'm no trailer expert and I did not stay at a Holiday Inn Express last night, so how about asking the trailer place

MrPeabody

07-10-2019, 5:51pm

I'm no trailer expert and I did not stay at a Holiday Inn Express last night, so how about asking the trailer place

Yes, if you are buying the trailer from a dealer of any kind, make the sale contingent on them doing this for you.

DAB

07-10-2019, 6:03pm

Yes, if you are buying the trailer from a dealer of any kind, make the sale contingent on them doing this for you.

this is a question about the truck wiring. apparently, GM leaves 2 wires unconnected, so you later have to have them connect them for you. :slap:

MrPeabody

07-10-2019, 6:10pm

this is a question about the truck wiring. apparently, GM leaves 2 wires unconnected, so you later have to have them connect them for you. :slap:

I know, but if the dealer you are buying it from has a service dept., they have the expertise to handle this for you. My dad bought several RV trailers over the years and every time he made the sale contingent on them doing all the necessary work on his truck, even a full hitch install one time. When I sold cars, once I sold a used Duramax one ton Dually and the guy made us pull all the fifth wheel stuff out of his trade and install it in the DMax at no charge. Dealers do what they have to do, within reason, to make a sale happen. Your issue is relatively minor.

JRD77VET

07-10-2019, 6:43pm

this gang has to know the answer:

have a 2013 chevy silverado 2500hd truck, it came with the Heavy Duty Trailer Wiring Harness Package, so I have an installed harness and electric brake controller on the lower dash board. the manual says it's all good to go...except that the wires for the Battery Feed (Red) and for the Trailer Brake (Dark Blue) are not connected to the fuse box, but the fuses are installed (page 9-96 of owner's manual).

i'm getting a trailer shortly, with electric brakes, and i need this mess to work properly first time out.

do i need to have the dealer do the final wiring connections, or is that something I could do? tried searching youtube, but didn't find any videos with this covered.

My previous Suburban ( 2001 2500 with towing package ) had a plug to connect to the fuse box where the brake controller wiring was connected to.

Mine worked perfectly.

You could look at https://www.gm-trucks.com/forums/ , they have been helpful.

DAB

07-10-2019, 6:58pm

I know, but if the dealer you are buying it from has a service dept., they have the expertise to handle this for you. My dad bought several RV trailers over the years and every time he made the sale contingent on them doing all the necessary work on his truck, even a full hitch install one time. When I sold cars, once I sold a used Duramax one ton Dually and the guy made us pull all the fifth wheel stuff out of his trade and install it in the DMax at no charge. Dealers do what they have to do, within reason, to make a sale happen. Your issue is relatively minor.

My previous Suburban ( 2001 2500 with towing package ) had a plug to connect to the fuse box where the brake controller wiring was connected to.

Mine worked perfectly.

You could look at https://www.gm-trucks.com/forums/ , they have been helpful.

i'm buying a water hauling trailer/tank combo from a place in TX. I want the truck to be ready to go when i go to pick up the trailer.

i'll check out the truck forum later (dinner time now). thanks.

JRD77VET

07-10-2019, 7:00pm

i'm buying a water hauling trailer/tank combo from a place in TX. I want the truck to be ready to go when i go to pick up the trailer.

i'll check out the truck forum later (dinner time now). thanks.

What brake controller do you have? ( make and model)

snide

07-10-2019, 8:05pm

this is a question about the truck wiring. apparently, GM leaves 2 wires unconnected, so you later have to have them connect them for you. :slap:

Reckon your truck was the last one down the line on Friday afternoon...

GRN ENVY

07-10-2019, 8:19pm

What kind of trailer harness do you have at the back. You should have a 4/5 pin and a 7 pin. Your 7 pin will have you standard, running, brake, L and R signals, and brake inputs. If there is an 8th pin it's for reverse. Most newer trucks have an option for factory brake controller. This could be why you have two wires with no connectors. You should be able follow those two empty wires to your 7 pin. You can wire in but it may not allow for your trailer to signal the brakes until an actual trailer is connected in the pin receiver in the bumper.

Hope this helps

DAB

07-10-2019, 8:37pm

What brake controller do you have? ( make and model)

What kind of trailer harness do you have at the back. You should have a 4/5 pin and a 7 pin. Your 7 pin will have you standard, running, brake, L and R signals, and brake inputs. If there is an 8th pin it's for reverse. Most newer trucks have an option for factory brake controller. This could be why you have two wires with no connectors. You should be able follow those two empty wires to your 7 pin. You can wire in but it may not allow for your trailer to signal the brakes until an actual trailer is connected in the pin receiver in the bumper.

Hope this helps

it's the factory brake controller. 7 pin. but the manual, as noted above, says 2 wires are run to the fuse box, but not connected. :slap:

GRN ENVY

07-10-2019, 8:44pm

it's the factory brake controller. 7 pin. but the manual, as noted above, says 2 wires are run to the fuse box, but not connected. :slap:

https://www.etrailer.com/tv-install-brake-controller-2013-chevrolet-silverado-90195.aspx

At the end of this video it shows needing to connect the wire in the fuse. The first half of the video doesn't seem to apply as youbhave a controller already. I believe you just need to get power to it.

GRN ENVY

07-10-2019, 8:51pm

https://chevroletforum.com/forum/silverado-fullsize-pick-ups-21/factory-brake-controller-diy-55257/page2/

Found this too.

JRD77VET

07-10-2019, 8:53pm

https://www.etrailer.com/tv-install-brake-controller-2013-chevrolet-silverado-90195.aspx

At the end of this video it shows needing to connect the wire in the fuse. The first half of the video doesn't seem to apply as youbhave a controller already. I believe you just need to get power to it.

:iagree: That is the exact same video I found.

Y2Kvert4me

07-11-2019, 4:34am

Imagine the potential liability an automaker would face supplying a vehicle optioned out for towing, with a factory-installed brake controller *but not connected to power*, with only a brief mention of that rather critical detail buried in the owner's manual. :skia:

This thread seems to confirm that suspicion:
https://www.silveradosierra.com/towing-trailers/factory-installed-brake-controller-question-t53137.html

I'm willing to bet you're already good to go. But even if not, unless you're hauling it back from TX full of water, I can't imagine the empty weight of the trailer being significant enough to need trailer braking for that trip anyways.
Like towing an empty car hauler, you'll basically need to dial the braking down to zero to not watch the trailer tires lock up and go up in smoke every time you tap the brakes.

:cert:

DAB

07-11-2019, 7:52am

I’ll test the circuits today with a multimeter

Imagine the potential liability an automaker would face supplying a vehicle optioned out for towing, with a factory-installed brake controller *but not connected to power*, with only a brief mention of that rather critical detail buried in the owner's manual. :skia:

This thread seems to confirm that suspicion:
https://www.silveradosierra.com/towing-trailers/factory-installed-brake-controller-question-t53137.html

I'm willing to bet you're already good to go. But even if not, unless you're hauling it back from TX full of water, I can't imagine the empty weight of the trailer being significant enough to need trailer braking for that trip anyways.
Like towing an empty car hauler, you'll basically need to dial the braking down to zero to not watch the trailer tires lock up and go up in smoke every time you tap the brakes.

:cert:

Bill

07-11-2019, 10:11am

Imagine the potential liability an automaker would face supplying a vehicle optioned out for towing, with a factory-installed brake controller *but not connected to power*, with only a brief mention of that rather critical detail buried in the owner's manual. :skia:

This thread seems to confirm that suspicion:
https://www.silveradosierra.com/towing-trailers/factory-installed-brake-controller-question-t53137.html

I'm willing to bet you're already good to go. But even if not, unless you're hauling it back from TX full of water, I can't imagine the empty weight of the trailer being significant enough to need trailer braking for that trip anyways.
Like towing an empty car hauler, you'll basically need to dial the braking down to zero to not watch the trailer tires lock up and go up in smoke every time you tap the brakes.

:cert:

I agree. Perhaps the two unattached wires are for some specific thing, like providing charging for a breakaway battery or for full time power for a RV.

I bet the trailer lights and brakes work right now as is.

Mike Mercury

07-11-2019, 11:09am

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQtK2HXdwKus7vgtWsrztnjKlZZ3LmngC5FHkMOCsecdfI8j5Xe9A

erickpl

07-11-2019, 12:04pm

I had a 2005 Avalanche and when I added an aftermarket module, it just plugged into a spot on the panel below the dash. Plug and go. Everything worked, including the electric brakes.

Not sure how a factory controller would be LESS plug and play... but I bet it is already working.

Hope it all works for ya.

Y2Kvert4me

07-11-2019, 12:23pm

Here's another thread (https://www.tractorbynet.com/forums/trailers-transportation/182726-gm-integrated-brake-controller-itbc.html) that suggests the unconnected wires mentioned in the manual lead to the under-dash pigtail meant to connect to an aftermarket brake controller.

With the OE controller, any reasonable person would expect it to be functional as delivered. If that's not the case, I wouldn't hesitate in raising hell with the dealer and for damn sure wouldn't pay anything for them to make it operational. You already paid for that option when you bought the truck.

DAB

07-11-2019, 12:43pm

Here's another thread (https://www.tractorbynet.com/forums/trailers-transportation/182726-gm-integrated-brake-controller-itbc.html) that suggests the unconnected wires mentioned in the manual lead to the under-dash pigtail meant to connect to an aftermarket brake controller.

With the OE controller, any reasonable person would expect it to be functional as delivered. If that's not the case, I wouldn't hesitate in raising hell with the dealer and for damn sure wouldn't pay anything for them to make it operational. You already paid for that option when you bought the truck.

i'm thinking of canceling my appt next week to have them address this, go pick up the empty trailer (less than 2000lb, ok to tow without brakes), and see if the harness is in fact not complete. pretty easy to check once connected. set brake gain to 5, apply trailer brakes, look for tire smoke.

:cert:

Y2Kvert4me

07-11-2019, 12:50pm

i'm thinking of canceling my appt next week to have them address this, go pick up the empty trailer (less than 2000lb, ok to tow without brakes), and see if the harness is in fact not complete. pretty easy to check once connected. set brake gain to 5, apply trailer brakes, look for tire smoke.

:cert:Exactly. :yesnod:
You don't need the brakes to bring the trailer home. The trailer lights (should) work even if those two wires specified in the manual aren't connected.

snide

07-11-2019, 12:50pm

Or, trade your POS Chevy for a Ford. :shrug:

DAB

07-11-2019, 12:51pm

Here's another thread (https://www.tractorbynet.com/forums/trailers-transportation/182726-gm-integrated-brake-controller-itbc.html) that suggests the unconnected wires mentioned in the manual lead to the under-dash pigtail meant to connect to an aftermarket brake controller.

With the OE controller, any reasonable person would expect it to be functional as delivered. If that's not the case, I wouldn't hesitate in raising hell with the dealer and for damn sure wouldn't pay anything for them to make it operational. You already paid for that option when you bought the truck.

thanks, useful thread.

yeah, you'd think that after paying for that option, you'd be good to go on day one, and not have to bring it back 6 years later when you get a trailer to hook up 2 little wires. i'll know more in about 3 weeks when the trailer is done and i go pick it up. :grouphug:

Bill

07-11-2019, 2:29pm

You can check if everything is functioning with a light tester and a friend. You won't have to guess, you'll know.

snide

07-11-2019, 2:31pm

You can check if everything is functioning with a light tester and a friend. You won't have to guess, you'll know.

Your method is less fun, and doesn't drive up the Barn Bucks count.

DAB

07-11-2019, 2:41pm

You can check if everything is functioning with a light tester and a friend. You won't have to guess, you'll know.

Your method is less fun, and doesn't drive up the Barn Bucks count.

tried testing with the help of Mrs. DAB (who can't see out of the cab) and a multimeter, but got buggy readings. yeah, maybe a light next.

gotta bank those barn bucks.... :beggar:

Bill

07-11-2019, 3:39pm

Your method is less fun, and doesn't drive up the Barn Bucks count.

Less fun? Dude, you need better friends!