skatville

Yes- 50 ohm resistors- IMPORTANT Rated at 1 WATT each. Now when making left or right turns, the camera for that turn works. I'm sure that can be a software improvement. Some cars and trucks have this feature by default. Like the Honda truck,

The antenna issue you mentioned is well known. They replaced it twice. At first it seemed to help, but anything they do seems to help for the short term. Eventually it fails. It doesn't seem to be effected by temperature or vibration. Maybe a GPS jammer somewhere !

Except for the XM radio, I did understand the functionality of that module. Thank you for the XM radio clarification. I really appreciate your input. I'm still trying to determine the problem my truck is having with the intermittent GPS/Nav failure. It's puzzling that I can go 900 miles with no problems and then all of a sudden it fails. I'm thinking some kind of interference, but from where?

This is the electronic module. Also called the F module. Home 2020 GMC Sierra 2500 HD Communication System Components 84882357 Module - GM (84882357)

You can ask why? I have a intermittent GPS/Nav problem that GM/GMC has been addressing since the vehicle was new (July 2020). I posted that issue about 17 hours ago. I have talked to a lot of GM techs, but they don't seem to understand how it all works as a system. I don't either, but I'm trying to. I want to talk to a high level system engineer, but I just can't reach them thru the GM service/support process.

Perfect answer. That is what I wanted to know. I assume all these radios, ONSTAR/AT&T cell, XM satellite and GPS are in the F module. The shark fin antenna services these three features. Could you confirm that?

HDMI? I don't understand your reply. HDMI is the interface cable to the display for video and digital audio if needed. Are you saying that GM uses that cable as an antenna for the internal hotspot connections for up to 7 devices inside your vehicle?

I did call ONSTAR and online advisors at GM. WiFi signals for connecting up to 7 devices in your vehicle do not come from the cell towers or any external connection. The internet data path is from the cell towers, but the WiFi router for connecting to devices is local in the vehicle. It's like connecting to cable internet in your house. You still need WiFi wireless router to connect to your devices.

Where is the physical location of the WiFi HOTSPOT router and the antenna? GM doesn't seem to know !!! A GM advisor said it doesn't have an antenna ,,,,, It gets the signal from the cell towers....... I don't think so. My iPad only has WiFi connections.

2020 GMC 2500HD Denali This intermittent problem was detected and all attempts to fixed it have failed since the vehicle was new in July 2020. GMC Service is at Dublin Buick GMC in Dublin, CA GPS/Navigation failure observations: 1-The GPS fault icon on the screen shows a red circle with a cross line. 2-Eventually, the navigation curser moves off of the direct path and erroneously to a location where there are no roads or into buildings. 3-The DIC compass display (N,E W,S, etc) still seems to work correctly and responds in real-time. On occasion, the DIC will show CAL in place of the compass direction. 4-I can’t confirm, but it seems like the outside temperature display does not update when the GPS fails. 5-Every time- NOTE: Every time, I call ONSTAR and the operator answers, the GPS failure icon goes away and the normal navigation icon appears. GPS/Nav starts working. This seems to last for a while. I have traveled for over 900 miles (no towing) with no problems at all. I got home and starting taking shorter trips to the store and etc. and GPS failures started occurring. Calling ONSTAR resolved the GPS error immediately. However, after some intermittent time, GPS error would re-occurred. Problem existed since new- July 2020. I find it impossible to contact an engineer who understands the system enough to help solve the problem. Next week I hope the F module gets replaced. Yes- Sept. 2022. The shark antenna has been replaced twice and the cable once. New software (firmware) was the last repair attempt.

I have a 2020 GMC 2500HD Denali with the Trailering feature. I had my GMC dealer install the rear trailer camera on a new 2021 travel trailer. They did a great job. It worked intermittently for months and would lose calibration. I had to take it back to the dealer many times to have the technician troubleshoot to problem. Finally, they replaced the camera. BINGO. All has worked perfectly for months now. I'm thankful I had the dealer install and backup the warranty. There may be a reliability/yield issue with camera. The only problem with the GMC now is the GPS. It has always been intermittent since new. The California Lemon law is being persued.

Here it is- April 19, 2021. I spent the whole day at the GMC dealership. GPS doesn't work or is intermittent. Rear trailer camera doesn't work or is intermittent. I have had this problem for some time since it was new- July 2020. The technician said there was an GPS error code and replaced the GPS antenna. It worked great when I left the shop- but failed before I got home. I called the service rep- He said push ON-STAR. I did a welcome call- bingo- GPS started working. Sample of 1 time. We'll see how well this works. At the same time I noticed the trailer brake lights after locking the truck with the FOB. This is the theft deterrent mode. The lights were flickering... I unlocked the truck and re-locked with the door lock. The lights behaved normally with a single flash every 30 seconds or so. The techician said there was an error code for the rear camera. They will order another one. I'm not optimistic at all. The whole Infotainment system is very complex with complex firmware. Seems like there is not sufficant diagnostic error catching codes to trouble shoot problems. My quess is tomorrow I will check out the camera and it will work. If it does, I still lose the calibration. That means I will need to remove the rear trailer tire to re-calibrate. YES- It doesn't calibrate with the rear tire mounted. These problems need to be elevated to higher hardware, software and firmware engineers. How can they fix these things if they are not in the middle of the trouble shooting battle ????

Here it is- April 19, 2021. I spent the whole day at the GMC dealership. GPS doesn't work or is intermittent. Rear trailer camera doesn't work or is intermittent. I have had this problem for some time since it was new- July 2020. The technician said there was an GPS error code and replaced the GPS antenna. It worked great when I left the shop- but failed before I got home. I called the service rep- He said push ON-STAR. I did a welcome call- bingo- GPS started working. Sample of 1 time. We'll see how well this works. At the same time I noticed the trailer brake lights after locking the truck with the FOB. This is the theft deterrent mode. The lights were flickering... I unlocked the truck and re-locked with the door lock. The lights behaved normally with a single flash every 30 seconds or so. The techician said there was an error code for the rear camera. They will order another one. I'm not optimistic at all. The whole Infotainment system is very complex with complex firmware. Seems like there is not sufficant diagnostic error catching codes to trouble shoot problems. My quess is tomorrow I will check out the camera and it will work. If it does, I still lose the calibration. That means I will need to remove the rear trailer tire to re-calibrate. YES- It doesn't calibrate with the rear tire mounted. These problems need to be elevated to higher hardware, software and firmware engineers. How can they fix these things if they are not in the middle of the trouble shooting battle ????

The truck (2020 2500HD Denali with towing package) checks the current on the running light circuit to detect a trailer. In my previous post above, I loaded the running lights and each brake light circuit with a 50 ohm ( 1 watt) resistor to the ground pin mounted in a trailer plug. I simply plug this in when the trailer is not connected to get the side camera to work. I disabled the theft deterrent feature, however, it is possible to use this feature as a trigger for an external alarm system.

It could a proprietary setup. I know there is DC power on the camera cable to provide power. You could distroy any camera you connect to it. I purchased the GM rear camera when I got the truck and had the dealer install it under my watchful eye. It's mounted on the center line of the trailer and 4 inches in height above the camera height on the tailgate. It is HD quality and works very well. Calibration and holding calibration for the transparency view are other issues I am having trouble with it.