Hello everyone,
I have now gone through 3 HMI modules. The first replacement was about a year ago. The second was about 6 months ago and as I was leaving the service dept parking lot, that new HMI module failed. The third replacement was 4 months ago and within a week, that new HMI module failed. I currently do not have working center console controls for air/heating, radio and GPS. The touch screen and steering controls do work. I have been trying to get my local dealership to get this HMI module replaced to no avail. They have numerous excuses and for the last two months will not answer my calls or return my calls. Today, the manager passed a message to another representative for me to call the General Motors. They will not be able to replace this unit. I have called General Motors and opened a case.
Does anyone have any suggestions on how to handle this problem,other than opening a case with General Motors. Does anyone have any idea why these HMI moduals do not work?
Appreciate the help.
Ruby

 

It sounds like something is shorting out the HMI modules and until the root problem is found, replacement units will keep failing. All that I can suggest other than what you’ve already done is to try to push to have them trace the electrical system leading to the HMI for potential issues.

 

So hold on a second....you said all the touchscreen stuff does work? So it's the physical buttons and ***** below the touchscreen that are broken?

If this is the case, it sounds like your HMI module is fine. It's the display and control panel assembly that's at fault.

Try this. Go into your underhood fuse box and pull out fuse 22. It should be a 10 amp. Pull it out for a few seconds, and then plug it back in. This should reboot the center display and controls. See if that brings everything back to life, even temporarily.

 

Thank you for this advise. When GM contacts me, I will talk about that. I am going to try the advise from Jeff V. that was just posted as well.
Thank you. Ruby

 

Thank you Jeff V. That is correct, this problem is only affecting the buttons in the center. The touch screen works fine. I will first thing tomorrow pull out the fuse.
Thank you. Ruby

 

Well, I pulled #22 fuse. The system came back on. Turned the car off. Three hours later turned car back on, still working. Five minutes into my drive, all failed.

 

This does sound like a wiring issue.

 

I would guess it is an intermittent short in the manual switches or in the wiring to it. This would suggest the controller they have been replacing went into a limp mode and was revived upon rebooting when it did not see a failure in the switches (or wiring loom). The fuse was a great recommendation.

 

That's along the lines of what I was thinking. Let me expand on it a little bit. But first, a little background.

The HMI module is the unit responsible for your touchscreen activities, media playback, and navigation, if you have it. It's up under the dash, above the hood release.

The physical buttons surrounding the touchscreen are a whole separate unit. The buttons communicate with the HMI is over a single wire LIN bus. It also talks to the radio and the two HVAC control units over LIN buses. These LIN buses run through an intermediate control box on the back of the touchscreen assembly, and out to the rest of the car.

Here's my theory. If the dealer really has been replacing the HMI all this time, they should have disconnected the battery in order to do it. This had the side effect of resetting the control panel, which may be where the problem actually is.

So I'm thinking it's the control face plate, or possibly the interface on the back of the touchscreen, that are bad. The HMI is fine, and always has been.

Control faceplates can be had relatively cheap on eBay. Display units are a little more expensive.

I'd start by disassembling the dash and making sure all the center display connectors are fully seated and there's no obvious damage to the connectors or wiring. If that all checks out, swap the control face plate. If it's still not fixed, the display unit itself is possibly bad.

 

My HMI has been acting flaky for the last month. When it dies one of two things happen, sometimes both: the clock disappears from the display and audio stops playing, also the favorite list reverts to just numbers (no custom names). However the HVAC controls continue to respond. The touch screen still works (navigation for example) but the physical radio controls (volume, home, back, etc) below are dead. Other times the entire touchscreen goes black. Either of these conditions can last 5 to 10 minutes or persistent thru two or three restarts of the car. It’s totally random. I’ve had it work fine for a week, then fail two days in row. Can’t figure out any logic to it, but think it might be battery related.

 

Thank you Jeff. Since my last update, after the first day of pulling the fuse, the second day the system was working and then failed 30 min later, third day system started working and failed 1 1/2 hrs later and 4 day to current has continued to be working. I am currently under extended warranty and plan on giving this information to GM. GM has been contacting me but are in the investigative mode. As soon as we can talk about who, what and where the work is to be done, I plan on having a personal talk with the tech. Thank you so much for your help.
Ruby.

 

Good luck. Hopefully they take a good long look at the control and display unit. In their defense though, troubleshooting intermittent electrical problems can be extremely tricky. I hope they get it sorted out soon.

 

Turned off Audio the other day. The next day when I tried to turn it on, the screen stayed black and the dash volume, FF/REW, Radio, Media, Menu etc buttons do not respond. HVAC still works.

I have had Sat/AM/FM radio and could control it from the DIC and steering wheel controls until morning while sitting in my driveway, the radio stopped finding sources.

I am less than 6 months out of warranty. Damnit.

 

Try it a few more times over the next few days. Make sure to drive the car or put it on a charger so you know the battery is fully charged up. My radio / HMI came back from the dead I know it sounds crazy but (knock on wood) its been working fine for nearly two months now

 

Dealer just called. They need to replace my touch screen. GM is willing to give $550 and reduce the dealers labor rate but it is still estimated to cost me $950!

11,000 miles and 4 months out of warranty. Not happy, not happy at all.