2020 GMC 2500HD Denali Location of WiFi HOTSPOT router & antenna

[skatville]

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. 

[nards444]

Id call onstar.  The fin on the roof handles onstar items which should be the antenna.  I might be wrong but NAV, internet or anything related to onstar is satellite driven and not tower driven.  

[skatville]

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.

[It's Tim]

16 hours ago, skatville said:

Where is the physical location of the WiFi HOTSPOT router and the antenna?

HDMI

[skatville]

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?

[newdude]

16 hours ago, skatville said:

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. 

 

 

The truck gets signals from the cell towers via the roof antenna driver's side.

 

The internal WiFi hotpsot antenna is off a coax cable off the back of the radio.  The antenna is quote:  "Within the instrument panel, on right side"

[skatville]

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?

[nards444]

I guess I have to ask, why?

[skatville]

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. 

[newdude]

1 hour ago, skatville said:

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?

 

 

Onstar, AT&T, XM and GPS pull from that antenna.  Not sure what you mean by F module?

[skatville]

This is the electronic module. Also called the F module.

Home  2020 GMC Sierra 2500 HD  Communication System Components  84882357

Module - GM (84882357)

[newdude]

1 hour ago, skatville said:

This is the electronic module. Also called the F module.

Home  2020 GMC Sierra 2500 HD  Communication System Components  84882357

Module - GM (84882357)

 

 

That isn't called an F module by GM so not sure why gmpartsdirect.com is showing it as such.

 

That module is the OnStar Telematics communication interface control module.  Handles the WiFi, bluetooth, onstar, GPS signal and cell signals.  XM is handled via the radio itself with a coax to the roof antenna.  

[skatville]

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?

[It's Tim]

4 hours ago, skatville said:

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?

Sorry my bad, above "communication interface control module" CICM. 

 

Water intrusion at the antenna on the roof can corrode/damage the cable which can cause all kinds of issues.

[skatville]

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 !