Late Model Tahoe Integrated Brake Controller ????

[JanFMiller]

Hello

Just took delivery of a 2019 Tahoe LS Custom, and I made sure it had the Max Tow Package.

This includes an integrated brake controller.

I'm still breaking in the Tahoe, only 100 miles on it so far, but today I hooked it up to my trailer to check things out.

All the lights work as expected on the trailer.

Tested the built-in trailer brake controller:

Pushing the gain controls or the manual lever triggers the display on the speedometer area.

Pressing the gain up/down buttons produces what you'd expect on the display: gain increases or decreases.

BUT: Moving the manual operation lever does nothing, the 'output' line on the display does not move.

I would expect it should. With gain at max and the manual lever held to max, the trailer moves, brakes don't seem to be applied. They were working fine when I last used it with my prior vehicle.

Tried with trailer mode engaged and displayed, no difference, trailer plugged in, no difference.

I haven't done any more testing yet, thought I'd ask first if the output should move without a trailer attached.

Or if there is something that needs to be configured to enable the controller, found nothing in the Owner's Manual about that...

Any help appreciated...

[clr]

Not sure about the Tahoe since my towing experience is all with pickups. The PU's that I have towed with mostly Fords, have a fuse and a relay that needs to plugged in to operate the trailer brakes. Many times even with a tow package installed the fuse and the relay can be found in the glove box or similar. Refer to your owners manual for the fuse and relay locations.

[Bama Rambler]

When you're hooked to the RV you're not seeing any warnings?

I'll check mine this evening, but as I remember without the trailer connected the slider will open the display in the DIC and display the gain number but the bar doesn't move.

[bikendan]

GM has a habit of not putting the fuse/relay in to activate the BC.

[Chief Lou]

My understanding is that the pinch bar is to set the threshold. While driving with the trailer attached to the TV at approximately 20mph, you use the pinch bar to set the threshold and bring the trailer brakes near lockup. When you release the pinch bar, the system now retains the threshold.

At least that’s what owners manual says...

[JanFMiller]

Thanks for the input!!!!

I've verified the trailer brakes are working as designed.

No warnings when the trailer is connected, nor does it say it IS connected.
All the lights work, running, turn, and brake lights.

From sleuthing around the iNet it appears the output display shows dotted lines unless the trailer is connected, and that's what I see with the trailer not connected. But with it connected I see the same thing.

Didn't see anything in the manual about activating the brakes, fuses/relays but I'll check again, no relay or fuse in the glove box...

Working on it now, will report back (:>

[Retired JSO]

I have a 2019 Tahoe with factory tow package. I found, the manual side of the controller will not work until the vehicle is moving somewhere above 10mph.

[JanFMiller]

After poking around some more I found:

I removed and tested very fuse that had the word 'trailer' in it's description. All good. Tahoe has about 1,000,000 fuses in 4 locations!

Using the tried and true method of checking the controller output with a 12v circuit tester lamp fails. The Chev says "Trailer Wiring Problem"... but at least I knew from that that something was hooked up.

Also found the 12V charging circuit is always hot. That surprised me, good to know because I run a 12V cooler in my trailer from that line, and I'd expect to have a dead battery in the morning. That circuit would power down on my Ford Flex when the vehicle was shut off.

When I was testing the trailer brakes, I also charged the emergency brake battery as it was too low to activate the brakes.

Cleaned the connectors one more time. Trailer end looked a bit suspicious, contacts seemed to have a pretty large gap. Used a screwdriver tip to bend them together.

Backed up the Tahoe, shut it off, removed the key. Hooked up. Started the Tahoe, it announced A Trailer Is Connected, and the output started to work!!!

I would really like to know HOW it determines a trailer is actually hooked up, what signal/presence of voltage/resistance it uses...?????

Well, I poked at a lot of stuff, but The Most Probable Suspect is the cheapo POS plug Forrest River used on my trailer. I'll replace it and hope for the best. 300 miles to go before I can pull the trailer, according to the manual...

OR... the e-battery must be alive??????

Thanks for the insight!!!
Jan....

[A2pfunk]

Originally Posted by JanFMiller

After poking around some more I found:

I removed and tested very fuse that had the word 'trailer' in it's description. All good. Tahoe has about 1,000,000 fuses in 4 locations!

Using the tried and true method of checking the controller output with a 12v circuit tester lamp fails. The Chev says "Trailer Wiring Problem"... but at least I knew from that that something was hooked up.

Also found the 12V charging circuit is always hot. That surprised me, good to know because I run a 12V cooler in my trailer from that line, and I'd expect to have a dead battery in the morning. That circuit would power down on my Ford Flex when the vehicle was shut off.

When I was testing the trailer brakes, I also charged the emergency brake battery as it was too low to activate the brakes.

Cleaned the connectors one more time. Trailer end looked a bit suspicious, contacts seemed to have a pretty large gap. Used a screwdriver tip to bend them together.

Backed up the Tahoe, shut it off, removed the key. Hooked up. Started the Tahoe, it announced A Trailer Is Connected, and the output started to work!!!

I would really like to know HOW it determines a trailer is actually hooked up, what signal/presence of voltage/resistance it uses...?????

Well, I poked at a lot of stuff, but The Most Probable Suspect is the cheapo POS plug Forrest River used on my trailer. I'll replace it and hope for the best. 300 miles to go before I can pull the trailer, according to the manual...

OR... the e-battery must be alive??????

Thanks for the insight!!!
Jan....

Just a random guess, but I bet it was the pins on your trailer's pigtail. It sounds like your TV was never recognizing that a trailer was even attached and so was not working correctly. My truck (a Ford) recognizes, like yours, as soon as trailer is connected. It then tells me (I'm guessing on resistance measurements) which lights are or aren't working on the trailer. In fact, it even seems to be able to tell the difference between the various trailers I hook up. Again, I am guessing that each one has a different electrical resistance 'signature'. Whatever it is, the truck can tell the difference. It then logs miles for that trailer and then remembers the different brake controller settings for each ones. Only time I've had problems is when the connection is bad. So I am guessing that your work with the screwdriver fixed the problem.

[Wileykid]

Originally Posted by JanFMiller

After poking around some more I found:

I removed and tested very fuse that had the word 'trailer' in it's description. All good. Tahoe has about 1,000,000 fuses in 4 locations!

Using the tried and true method of checking the controller output with a 12v circuit tester lamp fails. The Chev says "Trailer Wiring Problem"... but at least I knew from that that something was hooked up.

Also found the 12V charging circuit is always hot. That surprised me, good to know because I run a 12V cooler in my trailer from that line, and I'd expect to have a dead battery in the morning. That circuit would power down on my Ford Flex when the vehicle was shut off.

When I was testing the trailer brakes, I also charged the emergency brake battery as it was too low to activate the brakes.

Cleaned the connectors one more time. Trailer end looked a bit suspicious, contacts seemed to have a pretty large gap. Used a screwdriver tip to bend them together.

Backed up the Tahoe, shut it off, removed the key. Hooked up. Started the Tahoe, it announced A Trailer Is Connected, and the output started to work!!!

I would really like to know HOW it determines a trailer is actually hooked up, what signal/presence of voltage/resistance it uses...?????

Well, I poked at a lot of stuff, but The Most Probable Suspect is the cheapo POS plug Forrest River used on my trailer. I'll replace it and hope for the best. 300 miles to go before I can pull the trailer, according to the manual...

OR... the e-battery must be alive??????

Thanks for the insight!!!
Jan....

This doesn't surprise me. I have a Chevy 2500 with the IBC. I had some issues with the display on my truck, somewhat similar to you. Pressing the brake pedal, I would sometimes get no indication of brakes applied, sometimes it would, but immediately go to zero. Manual application would always work. I finally traced the problem to a broken wire on my trailer to one of the brakes.

These newer trucks with all the computer gizmo's are great, but can show weird indications when something is wrong. Unlike vehicles with all the sensors to tell the computer what is happening, the trailer braking system is dumb, so the computer only looks for "x" resistance in the line, and as long as it sees what it wants, it is "okay". When I applied the brakes, and although it was applying the brakes, it didn't see what it wanted, so went to zero. Why no "service trailer brake" error message, or no problems when I manually applied them, who knows. Only 3 of the 4 brakes were working on my trailer.

The battery for the emergency brakes is seperate, and is "switched" off, until the wire is pulled on the switch.

[JanFMiller]

Originally Posted by Wileykid

This doesn't surprise me. I have a Chevy 2500 with the IBC. I had some issues with the display on my truck, somewhat similar to you. Pressing the brake pedal, I would sometimes get no indication of brakes applied, sometimes it would, but immediately go to zero. Manual application would always work. I finally traced the problem to a broken wire on my trailer to one of the brakes.

These newer trucks with all the computer gizmo's are great, but can show weird indications when something is wrong. Unlike vehicles with all the sensors to tell the computer what is happening, the trailer braking system is dumb, so the computer only looks for "x" resistance in the line, and as long as it sees what it wants, it is "okay". When I applied the brakes, and although it was applying the brakes, it didn't see what it wanted, so went to zero. Why no "service trailer brake" error message, or no problems when I manually applied them, who knows. Only 3 of the 4 brakes were working on my trailer.

The battery for the emergency brakes is seperate, and is "switched" off, until the wire is pulled on the switch.

+1 on the E-battery. Mine is totally buried underneath the floor of the trailer ( it's a toy hauler I converted into what I call The Rolling Man Cave (RMC), spartan, but works for me.

Last trip, snowbird to TX last February, brakes quit working about 300 miles out. Icy, -18 degrees, fun!!! When I got to TX, crawled under and found a couple of the wires from the frame to the brakes were broken. Wire FR used is very brittle and doesn't like bending. Freed up some slack and reconnected them.
Found at that time the E-battery was not working. FR just drills a hole in the frame near the front jack, and joins the wire with Scotchlocks, no electrical tape or silicone seal or protection of any kind. Lots of salt used here, and the metal part that connects the wires was just ... gone .... Really need to re-wire it, shoddy work, but I sealed the connections and then sealed the bare unprotected hole they run into...

Have a new 7-way trailer plug on order GM recommends ( supposedly ), should take care of the problem...

pause...

baWAHAHAHHAHAHHAAAAAAAAAAAAAAAAAAAAA....

Thanks again for the help everyone!!!

[Wileykid]

When you get the plug, make sure you load the inside of the plug with dielectric grease. Even the one on your vehicle. It will help prevent problems.

Couple of years ago, Chevy/GM had a run of problem plugs on the trucks where water was able to seep in. A very interesting feeling when you are going down the freeway at 65 mph in heavy traffic, when the "service trailer brake", and "trailer disconnected" warning comes on.

[JanFMiller]

Originally Posted by Wileykid

When you get the plug, make sure you load the inside of the plug with dielectric grease. Even the one on your vehicle. It will help prevent problems.

Couple of years ago, Chevy/GM had a run of problem plugs on the trucks where water was able to seep in. A very interesting feeling when you are going down the freeway at 65 mph in heavy traffic, when the "service trailer brake", and "trailer disconnected" warning comes on.

Thanks, been doing that for years, and it is a good thing to do.

Installed a new plug today, problem seems to have gone away, but I was not impressed by the quality of the replacement, so will keep an eye out for something better. There were many on Amazon, from 4-12 bucks, but they all appeared to be the same thing...