ArrowsmithPML

The low quarter. I'm not near it right now so I can't tell you the exact Celsius figure.

My gauge barely moves whether towing or not with my 21 DMAX

I too have had many issues with the SD card in the 2021 3500 AT4 (6.6L DMAX). Card has been replaced multiple times but has not fixed anything. It stands to reason it could be the USB Hub or Harness for sure. This error does not occur on my 2021 Yukon Denali XL (3.0L DMAX).

Well it is cold and snowing here today (-12C) ok, not the -50 from other parts, but I am at sea level. Anyway, tailgate doesn't open - frozen shut. Had to get all sorts of lock de-icer on the hinges and such and i was able to finally get it open. This is a piss poor design and is a very large pain in the rear end for someone that uses the truck as NOT a grocery getter. Oh and the Kicker Audio has quit too. It is all heading into the shop inside the month. Does anyone have any work arounds? Cheers,

About 2 months ago we bought a 21 Yukon Denali XL DMAX. I'm sorry but if someone is claiming lags then there has to be something wrong with their VVT because ours is snappy. We traded a 17 6.2L and this is way better economy at 9.8L/100 vs 18.5L/100 and this is far better off the commuter line in stop and go. Biggest delay is the autostop BS that will be getting turned off here as the temperature drops.

We took it but I got what I wanted out of the deal. Now with only 585km on the clock I get a warning the DEF is low and yet it was fine today when driving it. I love sensors. Anyway, it is nice to drive, assuming this isn't a budding problem.

Yes, a bit of a commute... haha

My bill of sale / contract is signed by both parties. I'd say that is pretty solid. They don't seem to care, and I can see their point as they can easily sell it to someone else. For the record there isn't any MB Denalis anywhere.

So after waiting 17 weeks my wife's new 2021 Yukon XL Denali 3.0L diesel has shown up. Very nice! Trouble is it doesn't match the bill of sale. We ordered midnight blue with jet black interior and a white unit shows up... So far there has been no offer of admission of the screw up. Just oh well we can order another one. This time with all the chip delays, 5 to 7 months... ya, no thanks. They have attempted to pin this on me and I have said this is a you problem, not a me problem. Deaf ears. Not sure what to do here. Has this ever happened to anyone before?

2021 3500 AT4 and the SD card has an error. I've read through this just went outside to check to see if the card was locked. As it didn't say, I moved the slider forward, that was clearly unlocked as there were more errors, so I moved it back. No fix. Onstar has attempted it as well. Dealer wasn't overly helpful.

The stuff from GM is not hard to install. The toughest part is the trim re/re.

PIC 24 through 29 - The finished product.

PIC 23 - I installed a fuse block so to keep everything neat and tidy.

PIC 22 - I drew all the wiring diagrams so I would know what was what.

PIC 19, 20 and 21 - Loom, lots of it. Note that I will be installing some heat wrap on the ones that run above the block later today.

PIC 16, 17, 18 - Wires, wires and more wires. I used a lot of 14 ga wire. So far 22 wires came into the cab, noting that the winch and buggy whip wires are not yet installed. I tried to map everything, colour coding, labelling and building harnesses as best I could.

Morning, It was suggested that I place the write up on the custom gauge installation in this section so I will do just that. A bit of background: this truck is brand new with just under 8000 km on the clock. It has already seen -45C and some off road conditions. I am a business owner (Arrowsmith Project Management Limited) and this is one of my trucks. First: a special thanks to everyone who has discussed the upfitter switches using the GM parts. I was very excited about that and was going to go that way but with discussions at the local parts counter about being my responsibility and that it would void the warranty and such I decided to do my own thing as all of this 12V stuff just needs a source and a ground. No ECM or other modules to plug into etc. Second, because I bounce down roads everything has to be solid, secure and of industrial grade to not fall apart in the middle of nowhere. Here is the installation process. FYI get the right tools - in this case the trim removal tools or you could end up with scratches and nicks like this. (PIC 1) PIC 2 and 3 - OEM trim of the AT4 before PIC 4 and 5 - Pay close attention to how things come apart - watch all the videos and read all the existing write ups on removal of panels. This TAKES TIME. Go slow and be patient. There are 2 clips that will break if your removal of the console lower trim piece on either side is removed in haste. PIC 6, 7 and 8 - The removal process. PIC 9, 10, 11 and 12 - Switch locations and layout - plan this out carefully. measure as many times as you need to. Take lots of pictures. I opted to use the OEM location as best I could for 2 switches. These ones control my front light bar from Bright Source and Strands. It has a main ON/OFF and a secondary driving light in both amber and white. This resulted in first installing a SPST rocker and a SPST moment switch. The moment was later swapped out for a SPDT rocker. I had a little trimming to do under the knee bolster panel. PIC 13, 14 and 15 - Trimming the drivers side lower console panel - this was done to house the cluster of switches for all the other goodies I need. (Reverse Alarm (1), Buggy Whip (1), Overhead Rotating Beacon (2), winch (1) and rear facing service lights (1))

Ok I will have a look.

Hello, With all the support there is with the upfitter switches, I thought I would give others another write up on a full custom switch (and light install). If this is the right location for that I will add it tomorrow. Please advise.

My progress to date... Custom built headache rack to not block the cameras and for service lights and a yellow rotating beacon (tomorrow). Have the big 32" Strands Light Bar installed but not wired yet too. Company logos were today as well.

Thanks. I like to tinker but also to do it right. Installed the drivers side fuse block today and did a lot of shop cleanup (all those bits go everywhere).

Update, the truck is reassembled now. Still waiting for some fabricated items so I can place the lights but the interior is just about done now. I will point out that the side console trim has a slide in/out tab that wasn't identified on the write up and I broke them off. Had to glue them back and then all good. Anyway, see my 2 (1x on/off lit switch and 1 moment switch for my front light bar) and the 6 other switch locations on the side console. FYI I found another port on the passenger side in case others need more room to run wire through the fire wall. This was a time consuming re/re but I like the commercial grade stuff on a work truck over the other stuff.

You will see in the second picture there where the fit up of the dash switches is that I did some cutting to the bit behind the knee bolster. As well I have utilized the OEM fire wall port (trimmed the engine side with side cutters as recommended in earlier posts) and stuffed 10 of the 22 wires I need through it. I will have to find another way for everything else. I also have a coax for the VHF radio and another for the cell booster to come through there as well. Lastly the custom built head ache rack is getting ready for powder coating. So I am getting very excited. Cheers,

I made a lot of progress today but right now the truck cab is a disaster. I have placed the 2 switches where the up fitter stuff would go and I am placing the other 6 on the trim under the centre console.