2015 Chevy Silverado 2500HD w/ ITBC issue

Padua2 · 04-30-2021, 10:47 AM

I have a 2015 Chevy Silverado 2500HD that does not seem to have the ITBC system working.

By that I mean that:
1. the lights that normally light up orange, are not coming on at all. I can adjust the gain with the + - buttons, but, the light bars do not come on.
2. further, using the manual lever, or applying the vehicle brakes does not activate the trailer brakes at all.
3. I do not see all the fuses as per owners manual, they all seem ok.
4. I intermittently see a "Service Trailer Brake System" message, but it goes away quickly and does not display again, for weeks or months.

I know it is not the trailer, as I had that checked, so the issue is with the truck itself. Has anyone had a similar issue? Any simple fixes? Thanks all for any help.
regards

**Mr. Dan** · 04-30-2021, 10:52 AM

Quote:

Originally Posted by Padua2

I have a 2015 Chevy Silverado 2500HD that does not seem to have the ITBC system working.

By that I mean that:
1. the lights that normally light up orange, are not coming on at all. I can adjust the gain with the + - buttons, but, the light bars do not come on.
2. further, using the manual lever, or applying the vehicle brakes does not activate the trailer brakes at all.
3. I do not see any faulty breaker switches, they all seem ok.
4. I intermittently see a "Service Trailer Brake System" message, but it goes away quickly and does not display again, for weeks or months.

I know it is not the trailer, as I had that checked, so the issue is with the truck itself. Has anyone had a similar issue? Any simple fixes? Thanks all for any help.
regards

I don't think you should be looking for "faulty breaker switches"; I think you should check your owner's manual for fuses and check the applicable ones.

GXPWeasel1 · 04-30-2021, 10:56 AM

I had that happen to my 2015 1/2 ton Silverado. Not the same truck, but I'm guessing the same taillight wiring, and brake controller.

I cleaned all the connection points for the trailer wiring harness under the back side of my truck. Took them apart, cleaned, and sprayed them with some dialectric grease ( I know I spelled that incorrectly). I also cleaned up my trailer plug, and bumper end of the plug on the truck really well, and filled with the grease as well.

This completely solved my issue, and I just keep up on the use of my grease. I frequently back a boat in the water pretty deep as well though, so that could exacerbate my "problem" which is why I keep the grease in the connections.

llr · 04-30-2021, 10:57 AM

Now real ideas, I just want to point out that I have seen a number of post where truck and trailer were inspected multiple times and both confirmed "good" before the actual issue was found.

Try in a safe location to pull the trail break away cable then move move the trailer. It should move very hard if at all. If this works try jumping the +12v & brake wires in the 7pin plug and try to pull it again.

Padua2 · 04-30-2021, 11:27 AM

Quote:

Originally Posted by Mr. Dan

I don't think you should be looking for "faulty breaker switches"; I think you should check your owner's manual for fuses and check the applicable ones.

I meant : checked all fuses as per owners manual" . I have corrected my original post. Best Regards

Padua2 · 04-30-2021, 11:29 AM

Quote:

Originally Posted by GXPWeasel1

I had that happen to my 2015 1/2 ton Silverado. Not the same truck, but I'm guessing the same taillight wiring, and brake controller.

I cleaned all the connection points for the trailer wiring harness under the back side of my truck. Took them apart, cleaned, and sprayed them with some dialectric grease ( I know I spelled that incorrectly). I also cleaned up my trailer plug, and bumper end of the plug on the truck really well, and filled with the grease as well.

This completely solved my issue, and I just keep up on the use of my grease. I frequently back a boat in the water pretty deep as well though, so that could exacerbate my "problem" which is why I keep the grease in the connections.

Did all that. Still same issue. BTW, my connections are like brand new. No corrosion or dirt al all. Truck has barely 45,000 miles on it.
Best Regards

Padua2 · 04-30-2021, 11:34 AM

Quote:

Originally Posted by llr

Now real ideas, I just want to point out that I have seen a number of post where truck and trailer were inspected multiple times and both confirmed "good" before the actual issue was found.

Try in a safe location to pull the trail break away cable then move move the trailer. It should move very hard if at all. If this works try jumping the +12v & brake wires in the 7pin plug and try to pull it again.

When I pull the trail break away cable, this works. Meaning that that the brakes on the trailer work as they should. We also connected the trailer to a friends truck that has the same hitch, and the trailer brakes work as expected on a different truck.

High Country Duramax · 04-30-2021, 12:14 PM

There’s an issue with the brake controller most likely. I had to have mine replaced, I think it’s fairly common.

aeblank · 04-30-2021, 12:16 PM

Google around for your service trailer brake message. Many reports and some "solutions". Relays, modules, wiring, corrosion in connectors, fuses, etc...

denville · 04-30-2021, 12:31 PM

The new brake controllers have to sense the resistance of the brakes to determine if it is 2 or 4 wheel brakes. That is why the trailer connection must be really good. Clean the connection even though it looks good.

denville · 04-30-2021, 12:39 PM

Read this https://static.nhtsa.gov/odi/tsbs/20...81241-2280.pdf

bq6zj0 · 04-30-2021, 12:54 PM

Roll over image to zoom in

ACDelco 23114650 GM Original Equipment Trailer Brake Power Control Module Assembly is on Amazon for 1919. price has went up and three day delivery. this fixed mine and is GM orginal parts for 2015 Silverado. took me ten minute to replace. On left side under spare tire there is two boxes be sure to match number so you get right box for brakes to trailer. They have a six pin chip that blows causing a short in the box.. You can fix this and safe almost 800 dollars is what chev dealer want here in Georgia......

RStormC · 04-30-2021, 01:39 PM

I recently had this issue when I lost my trailer brakes on the interstate. I have not yet had a chance to investigate thoroughly, but my internet research indicates to do the following.

1. Inspect and clean the 7 pin plug and receptacle.
2. Bungy the cord cover on the truck after plugging in the trailer cord. There are several references to GM being aware of the problem but not offering to fix it. It seems most prevalent on trucks where the 7 pin plug cover is on the top and opens down.
3. If these do not work, replace the trailer control module located above the spare tire under the truck. Internet sources report that this can be purchased online for $35-$40, whereas as GM or Chevy dealer will charge at least a couple of hundred to diagnose and replace the module.

I am in the process of working the problem out, but it is not convenient to keep hooking up and driving around waiting for an intermittent problem to reappear.

sundancer87 · 04-30-2021, 04:55 PM

You can do all the cleaning and inspecting, even replace the cabin brake controller and you may still have the problem.

Most likely a front wheel speed sensor has gone bad and is causing the problem. You can replace it if you have the tools and know how and know which one it is or let the dealer do it.

RStormC · 04-30-2021, 06:53 PM

In my case I followed the instructions in the trucks owners manual to disconnect, shut the truck off, and turn the switch to acc. Because the message came back up, the fault is with the truck, not the trailer.

autoguy40 · 04-30-2021, 08:07 PM

I have a 2011 2500hd.
When I drive the truck in the rain I have several dash lights come on as well as service trailer brakes. There is an electrical connection box under the truck bed, close to rear bumper just off centre to drivers side. These trucks are known for having a moisture seepage issue in to this box. Once it dries out after a rain all goes back to normal. I have stayed the outside of the box with undercoating and haven’t had an issue since.

**Flybob** · 04-30-2021, 08:12 PM

Did you pull the breakaway switch while connected to the TV. This can damage the controller or blow a fuse.

autoguy40 · 04-30-2021, 08:20 PM

I have and the trailer brakes worked as they should.

autoguy40 · 04-30-2021, 08:24 PM

The trailer brakes have always worked correctly even when the dash lights and service trailer brake lights were on. Once it dries up, usually a day or so after a rain, the dash lights go out. The trailer brakes continue to work properly.
Hope this helps

LJS1211 · 04-30-2021, 09:22 PM

I no longer own the truck but I did have a 2015 Chevy Silverado 2500HD and experienced the same issue. It ended up being one of the 30amp fuses under the hood. Not sure what caused it to blow but when it did I had all the lights working but no trailer brakes. I’ve since upgraded to a 2021 Chevy Silverado 2500HD but I still carry a lot of extra 30amp fuses just in case. Good luck and hope you can get it working.

You may also like: