u/thaughtless

For awhile, I've been experiencing an odd issue that I couldn't pin down. When towing my travel trailer, I'd get these intermittent issues where the dash would pop a warning message that the trailer brakes had disconnected and to check wiring. Most concerning, was that this would happen particularly when going down hills; the very moment you want brakes to work lol. Pull to a stop, and hey presto, the trailer brakes reconnect.

I'd looked into everything on the trailer, checking the grounding, and even switching out the 7-way plug for a better quality plug, utilizing the same blade type brand that GM uses.

Using the joy of Claude, AI helped me find out what I believe is the actual cause - it's the trailer brake controller in the truck itself. Apparently, when you have a trailer that has solar and a lithium battery, because the battery runs at a higher voltage than the truck expects, it misinterprets this signal and causes a disconnect. Claude referenced this article: https://www.gm-trucks.com/service-trailer-brake-system-why-your-2023-or-2024-chevy-gmc-may-display-this-message/

Thanks GM. Even the dealer didn't know this one. It's going in for a trailer brake module replacement on Wednesday.

My wife and I got back from a roadtrip from Orange County, CA to Bryce and Zion national parks, in utah. Thats a 1000+ mile roadtrip, towing a 30 ft travel trailer, and dealing with 100 degree heat. Not to mention the significant elevation gain. 

We drove on day 1 from OC to the valley of fire state park in Nevada. We banked on a few charging stops on the way, planned with buffer and for pull thru chargers. Two main factors were the heat and the altitude climb. Barstow, CA was the first stop. Tesla has a pull thru here so this was easy. 

Next stop was Jean, NV. A very big Tesla charger, with  100 chargers and 2 pull thrus! Thanks Tesla. 

Those got us to the valley of fire state park, and by the time we reached there it was hot. 117deg hot. Im not gonna lie that I thought the truck might get a service warning, but thankfully the latest update had been applied to prevent over heating and we got there fine. The in cabin AC had definitely dialed back though to do its best to focus on the battery. It was definitely tough on the truck, but even with a diesel, that kind of heat is pretty grueling. We saw several trucks/trailers on the side of the road, and one on fire.

The truck probably spent the next hour at the campsite with the fan on high to try cool down. Putting it in the shade of the trailer helped. Once it was cooler, we put it on the 50A campsite to charge.

The next day we made the next leg to Bryce, UT. More climbing. More heat. That heat pump in the truck was certainly getting a workout. As a result of both the climb and the heat the range really sucked....0.7mi/kwh. No trip calculator can seem to accurately account for that.

We stopped in Mesquite, UT and used an Electrify America charger, parking on the back side of the charger so as not to block any stalls. One more charge stop after that and we made it to Bryce safely. Thats quite the climb....8000ft, in the heat.

What we discovered at Bryce, started to be a consistent pattern. If you ask whether you can charge from your campsite, quite often you're met with acceptance. Rubys RV park and campground is EV friendly so we charged off the 50A there. The trip down from Bryce to Zion was pretty uneventful, and we got there on one charge without issue.

It's interesting the difference in EV attitudes though. Next campsite was Zion river resort just out of Springdale. Not only does the campsite explicitly ban it (even when I asked to pay) but there is nothing in that entire town for EV charging.. So that means you're driving 25mi to the nearest Tesla charger on the I-15. Not great. 

On the way home we stopped one night through Vegas. Another great EV friendly campsite there called Oasis RV park...charged again off the campsite with their approval. Highly recommend it.

Overall, the truck did really great. Its really so effortless towing with this truck, its super stable, the super cruise with a trailer really takes the pressure off driving, and so long as you plan ahead, EV stops are very manageable. Loved it.

But make sure you are planning ahead. Heat and altitude definitely impact range, and there was a lot of climbing in this trip which brought the average to around 0.8 mi/kwh.

I wrote an EQ app to replace the app that was pulled from the app store.

It works by presenting a series of tones at different frequencies to essentially tune the audio to your vehicles speakers and your own ears. There's of course a manual EQ override function - and works across 10-bands of frequency vs the usual 5 or so. It takes the Sierra EV audio and brings it to life - I'm sure it will work just as well with other vehicles also. I need about 15 people to test it before I publish it in production. If anyone is interested being part of the test program, please send me a DM.

Edit for credits:

Close to bringing this to market in a small scale for off-road use, so just gauging interest for now. This was a project to solve a need originally our family had, but has evolved into something much cooler.

Brief feature walkthrough on my beta CarPlay integration (lvalen91's carlink_native):

- Single Pane WebView or CarPlay

- Any combination split-view of WebView, CarPlay, or optional RTSP camera stream

- Resizable PiP overlay anywhere on screen of RTSP camera stream. Auto detection of camera IP and UI config improvements.

- The camera is a Tapo C121 (though any camera that supports RTSP will work). Camera is joined to the truck’s WiFi and communicates with the app via RTSP.

- Dongle is a CPC-CCPA flashed with a custom firmware I ended up writing myself, with my iphone directly cabled to it. The CPC supports wireless CarPlay but GPS can be spotty (this is just an inherent wireless CarPlay via dongle issue - wired is stable)..

If interested, shoot me a DM!

Finally made the switch to 18" wheels. To keep it safe, staying with the same offsets and bore size, I managed to find some Sierra EV Elevation wheels. Looks better to me than the Hummer ones. I put 285/75R18 wrangler territory at tires on them to keep the diameter the same.
GM now wont offer a calibration to a different wheel diameter unless you could spec it on that particular trim originally - and that goes as far as battery size differences between standard/extended/max range. Super dumb. So this becomes important.

Fun fact. Make sure also if they are jacking your truck up, they put it into service mode or you get a service suspension error on the dash - it resolves itself after about 25mi. But was annoyed they didn't do this first.

Too early to tell on range but a cursory check indicates range is about the same. I expected better actually. This shift represents about 25lb per corner of reduced unsprung weight. We will see how it goes over time.