Chadw90

Yes I have. Battery voltage at brakes with controller on 10. once the trailer battery was fully charged, the brake voltage remains the same, but amperage drops through the floor. I can pull 10 different models of new trailer out of the lineup (we sell trailers at my work) or 10 used trailers, all the same until i put the diode inline. try to explain voltage vs amperage to a dealership auto mechanic is like trying to explain colors of the leaves in fall to a color blind person. Just doesn’t resonate lol. Not sure why something like a trailer brake controller needs to be over engineered by running it through it’s own logic controller, what was wrong with 12V direct battery wire to brake controller to brakes.

Magnet brakes here too. Electric hydraulic discs would be cool though

Get what you pay for I guess. Should have bought the Denali Ultimate for $130,000k CAD. Shame on me for buying the poverty AT4 for $106,000 lol. I should have kept my 2017, enough technology to keep you happy and not enough to have little gremlins like this. Id be tempted to go back to a 2017-2019 if I could find some gem that was just a sunday truck and low miles.

My problem was/is different than yours i guess. Yours is disconnecting, mine is dropping amperage as it seeing the trailer battery reach almost 13v’s. Once I put the diode inline, it prevented back-feeding and tricked the truck. My symptoms were strong brakes at the start and once the battery got charged up, Id have to turn the brake controller to 10 to get it to slightly grab the brakes. Most people wouldnt notice as they dont periodically just check their brakes along the trip. The symptoms are same as brake fade, but it happens with every trailer of all configurations. Like you, Im not impressed. When I go to buy a new truck, if GM hasnt rectified this, I may entertain a Ford, possibly a (gulp) Dodge.

On the 12v wire. I bought a short extension cord, opened it up and installed a diode inline on the 12v wire

Bilstein 5100’s on my last two Duramax trucks(2017 silverado 2500 & 2023 sierra at4 2500). Night and day difference. Much more planted feeling. No dancing on washboard and no hopping on the highway.

Found that it is an aux fill port. The fitting is open on the bottom side. No straw/tube attached.

I am thinking probably not l, just due to the fact that it has a sealed cap on it. Not a vent of any sort. My dodge had an auxiliary pickup tube there so you didn’t have to install a draw tube. Was hoping thats what this is for but would like to know before dropping the tank or pulling the bed

Does anyone know what the third tube into the sending unit on the L5P is for? My truck is a 2023 GMC 2500. There is two quick connect lines (supply & return) and then a third one with a quick connect cap on it. I am looking to install a Webasto or Espar and am wondering if thats a draw straw into the tank Thanks

If thats your case, the tech running the alignment machine isnt doing it right. When they perform a wheel alignment, they have to align the front end to compensate for the crown in the road. 2% slope is an average for watershed. If they didnt dial in the front end to compensate for this, your truck would have a heavy pull to the shoulder. Either way, mine is clocked to the right at 1 o'clock in the right hand lane and about 2 o’clock in the left hand lane. When you let go of the steering wheel, ideally the truck should have a very very slight/gentle pull to the shoulder in the event of an unresponsive driver, the ditch is the safest. Everyone likes a straight driving truck, you usually have to ask for that, this one is straight like its on a set of train tracks, just the steering wheel off.

My 2023 gets an alignment every oil change due to the wheel being off center. Its like it is on a trip meter. At roughly 8000kms, its off to either the right at 1 o’clock or left at 11 o’clock. To and from work i have option A which is two different highways(one south, one east) or option B which is one east and then south. Doesnt matter which way i take there or back, same issue. let go of the steering wheel and it tracks perfectly, no pull to the right or left, just the steering wheel off. No abnormal tire wear, or vibrations. Does this regardless which tires are on(i have a set of winter tires on factory rims and my all terrains on factory rims). I even ditched the OEM Hankook MT2 tires that came on the truck stock. We have tried max tire pressure for the truck, bumped it down to 50psi, back up to 60 front 65 rear. Nothing helps. They do the alignment and its bang on for about 6-7000kms and by 8-9000kms its at 11 or 1. At 10,000kms, i take it in for oil change and alignment

I did my first two oil changes at 5000kms just to get any break in junk out. Didnt let my truck idle, and put a load behind it as often as i could. Even towed a skidsteer around when it wasnt needed. i just rolled over 40,000kms a few weeks ago and fuel economy has gotten better, even with winter diesel up here in Saskatchewan. I have a Banks idash for monitoring and regens have gone from 900kms-1000kms between regen to 1200kms - 1350kms now. might be a coincidence but seems like it all happened at 40,000kms. i also change my fuel filter at every 10,000kms regardless what the monitor says, engine oil and filter also at every 10,000kms with rotella t6 5w40. like anything, good maintenance yields a good truck.

Interesting. This makes sense. One bad rotor out of four could definitely be the issue here and honestly a relief. I was thinking if one brake line or caliper had a defect sending too much fluid to the right rear or something like that. Try to explain or have that diagnosed by the dealer lol. I will just toss a set of new rotors on if the dealer wont under warranty being this has been an ongoing issue

I have a pulsating when braking too. They turned my rotors at 26,000kms free of charge due to my trailer brake module taking since new to diagnose. Just figured rotors warped due to not having any trailer brakes and big loads. but just put my winter wheels on tonight and right rear has 39 thou runout, left rear 4 thou. Didnt bother measuring the front as the right rear is enough to cause it. No steering wheel shake. Calipers slide nicely on the pins, pads are worn evenly. I will ask the dealer tomorrow but i would imagine a new set of rotors are going to be on my dime. But curious on why they warped again. I do not brake hard like the OP lol. I use my exhaust brake and drive as conservative as possible, Im always on the quest for the best mileage possible.

Ya i get what you’re meaning here. My big trailer, i have a truck end plug wired to a solar panel to keep the batteries topped up while its parked, so my brake fault is immediate when i hook up. My small enclosed has a trailer brake battery maintainer, my truck runs at 14ish volts when driving, so 13.3 with a diode in line, still enough to trickle charge that little battery. Brakes work great when i first hook up and within 15mins, they are weak. It mimics brake fade. I unplugged the battery today and they worked 100% all day. All other trailers that i tow for work, i dont care if they get a rapid charge or not. I could tow work trailers 5 times a week and it be different trailers each time. We just grab one out of the new line up and toss a dealer plate on it. this is where i plan to get a 3’ extension cable and put a diode in line, just for those trailer that I dont own. what DC to DC converter did you use. Id put one on each of my personal trailers.