Onstar Issue. Fuse Location and Other Troubleshooting.

aDave · February 10, 2020

Hi guys,

Today, I was confronted with a problem that I first thought was bluetooth/phone related, but after spending more time at the truck (2015 Sierra 1500 Crew Cab) and here doing some searching, I'm inclined to believe my problem is (in part) tied to Onstar. Please bear with me.

The first item I noticed was that when making or receiving calls via bluetooth, I could hear the caller through the audio system, but they could not hear me. I went through unpairing and pairing multiple phones, and the problem persisted which pointed to the problem being the truck and not the phones.

While working in the cab, I noticed that the green LED in the rearview mirror was not lit. I tried the Onstar push button, and I had no luck in reaching a representative. Further, the Onstar icon on the display home screen is greyed out while all other icons are well lit. Lastly, my phone no longer sees a Wi-Fi signal from the truck, and the "GPS" on the Nav display has a red line going through it. Despite the red line, Nav still tracks the vehicle on the road, but the movement of the truck on the display is more jerky than normal. The one thing that is still okay is reception for Sirius XM.

The first thing I'd like to check is the fuse for this system, but I'm having a hard time finding one. Does anyone know which fuse may power this stuff? The manual mentions a fuse for the rearview mirror/universal garage door opener, but I'm not having a Homelink issue. Would this be the right fuse (#3 on the driver's side panel), or should I be looking somewhere else?

As far as the phone mic issue, is that microphone powered or tied into Onstar, or are they separate?

If this ends up being a fuse issue, then great. But, I've seen posts related to the sharkfin leaking and I'm wondering if this could have been the cause of what I'm dealing with. Coincidentally, it rained last night, but I'm not seeing any sign of wetness in the headliner. However, I've seen posts where there might not be any sign of a leak until the headliner was pulled and the antenna was examined. Anyone have a link for a good tutorial/video on how to pull the headliner? I have not really worked on my truck that much, so I could use a good step-by-step in order to guide me through if it comes to that.

While I'm somewhat keying in on the power (fuse) and the antenna leaking as being concerns, is there anything else I'm missing? Is there a Onstar module somewhere that should be examined?

Sorry for such a long post, but I wanted to try to cover a problem that could be multi-faceted. Thanks in advance for any advice or information you can offer. Best regards.

Dave

Edited February 10, 2020 by aDave

tbarn · February 10, 2020

Right side IP fuse box. Fuse #F23DR. 10A Pull it and leave it out for a couple of minutes. Reinstall ( a good one ) and try. You might get lucky. Onstar is notorious for what GM calls logic lockup. If it is an antenna issue it wouldn't affect bluetooth.

tbarn · February 10, 2020

Fuse 23 may be listed as ABS because it also runs that. Make sure the key is OFF when you pull the fuse.

Edited February 10, 2020 by tbarn

aDave · February 10, 2020

32 minutes ago, tbarn said:

Right side IP fuse box. Fuse #F23DR. 10A Pull it and leave it out for a couple of minutes. Reinstall ( a good one ) and try. You might get lucky. Onstar is notorious for what GM calls logic lockup. If it is an antenna issue it wouldn't affect bluetooth.

Great, thank you. Fuse #23 in my manual is labeled Air Bag/Info, so you've given me a good starting point. I know this is a stupid question, but do I simply pull at the bottom of the panel to open it? I was trying the drivers side and was unable to pull it open. Does it REALLY need a good tug?

While still searching around, this guy seemed to have the same problem I am. His solution is at the end of his thread. Is his solution addressing things on the same line as you have?

He disconnected his negative cable, and if I've read correctly, he held the disconnected negative cable to the positive side to discharge the system fully. Is that safe, or should I just disconnect both cables to try a reset?

Thanks for your help.

Edited February 10, 2020 by aDave

tbarn · February 10, 2020

The cable toching is no longer recommended because of potential voltage spike. Too many sensitive modules. You can do a similar process though. Disconect both cables and use a test light to connect the cables. A test light with an actual light bulb. The touching just speeds up the process of draining the modules. Not required though. If you have time, just disconnect the neg cable and walk away for awhile. Overnight would be great.

aDave · February 10, 2020

3 hours ago, tbarn said:

The cable toching is no longer recommended because of potential voltage spike. Too many sensitive modules. You can do a similar process though. Disconect both cables and use a test light to connect the cables. A test light with an actual light bulb. The touching just speeds up the process of draining the modules. Not required though. If you have time, just disconnect the neg cable and walk away for awhile. Overnight would be great.

Well, I don't know if it was luck or not, but I ended up not having to go this route.

This morning, I pulled the fuse to inspect it, and it looked fine. Based upon your recommendation, I waited a few minutes before putting it back in the block. I then started the truck to check the system, and the rearview mirror had power,. When I saw that was seemingly back to normal, I made a call with bluetooth, and I was able to be heard through the microphone.

So, whether or not the solution had something to do with pulling the fuse, or just sitting overnight before restarting again, it appears all is well. So, Tom, I appreciate the help.

ETA: Now I know why the fuse panel covers were so hard to remove. Those posts can be a bear to get loose.

Edited February 10, 2020 by aDave

Ryan Thousand · July 11, 2024

Anyone know where this fuse is on a 2022 Chevy 3500? Same issue but I don’t see the airbag info fuse only info2. Pulled it and it turns off the radio not the lights by the mirror. Also unplugged negative cables for over 4 hours and still no dice.

MikeBMW · July 11, 2024

1 hour ago, Ryan Thousand said:

Anyone know where this fuse is on a 2022 Chevy 3500? Same issue but I don’t see the airbag info fuse only info2. Pulled it and it turns off the radio not the lights by the mirror. Also unplugged negative cables for over 4 hours and still no dice.

For a 2022 3500?
Might want to check here:
https://www.gm-trucks.com/forums/forum/240-2020-2024-silverado-hd-sierra-hd/

Edited July 11, 2024 by MikeBMW