[Seth2022]

I have a 2016 Chevy Colorado, 4 cylinder, four wheel drive, 55k miles. Video link at the end.

Inconsistently, when I am driving down the road and I turn on the high beams or even role down the window, my whole truck does the following: goes into limp mode, the locks jump up and down, the windshield wipers go off at least once, the whole dash shuts down, radio turns off, etc. I let my foot off the gas, let go off the highbeams or window button, the rpms drop and everything turns back on and the truck returns to normal.

First thought this was related to the traction control/abs issues since those are the codes it throws and the lights that come on after an incident like this. For kicks I went ahead and replaced all of the speed sensors in the wheels to see if the problem would go away. I figure this is unlikely because it seems like a much deeper electrical issue. Check out the video and forget what i say about the sensors at the beginning, it's irrelevant. The issue was pre-existing.

I checked all of the connections to the battery, I've checked all the relays and fuses, at this point I'm wondering if I should call an exorcist. Kidding but the only thing I can figure where the lights, the windshield wipers the dash instrumentation, etc. all come together has to either be in the fuse box or in the computer.

Chevy dealership were A holes, said they can't get it to happen again and cleared all my codes, said the diagnostic came back clear. Now i have a video so it's hard to deny.

Video too large too upload, link here: New video by Seth Freeman

 

[American Truck]

Bring it to another Chevy dealer and show them the video.

 

[Hunter62]

How old is the battery and has it been tested?

check wire looms for chaffing around bolts and such

 

[ARCowboy]

Request a "ride along" from that dealership. Might take a few more days to get their service manager or whatever a free space on the calendar, but that's what I did for my front output shaft seal. I drove him around and took a route I knew would cause the issue, he heard it, they put it up on a lift, replicated it, and replaced it.

But to Hunter's point, how old is the battery and have you had it load tested for free at Advanced/AutoZone/Etc ? I would assume there's a reason the alternator goes into high output when the brights or wipers are turned on, and a dying battery could probably cause all of these issues.

 

[Speedy4x4]

My 07 f350 work truck had the common problem of battery saver relay going out, 02-07 super duty.
It is in the gauge cluster.
Flickers on and off occasionally, when it does, can not get out of park, turn signals do not work, windows do not work, radio does not work, all comes on and off.
But in a superduty, not a gm.

When you say the rpm drops, does it just drop on gauge cluster, or the engine drop?
Start nice and easy every time?

I hate stealerships, if not under warranty, I would look for good small shops.

 

[Seth2022]

How old is the battery and has it been tested?

check wire looms for chaffing around bolts and such

Battery is about a year old, but i am not sure it's been tested. For the harnesses, i had my wife sit in the truck and hit the lights and watch the dash while i grabbed and wiggled and exposed harness i could see or touch. Nothing. No chafing found. I'll get the battery checked. Can't hurt at those point.

 

[Seth2022]

My 07 f350 work truck had the common problem of battery saver relay going out, 02-07 super duty.
It is in the gauge cluster.
Flickers on and off occasionally, when it does, can not get out of park, turn signals do not work, windows do not work, radio does not work, all comes on and off.
But in a superduty, not a gm.

When you say the rpm drops, does it just drop on gauge cluster, or the engine drop?
Start nice and easy every time?

I hate stealerships, if not under warranty, I would look for good small shops.

The truck starts fine, only once did it fight me to start. However, that only lasted 2 key turns and has never happened again.

As far as the rpms. It down shifts and the RPMs shoot way up, then i just let my foot off the gas, and second later it suggests back to where it should be. I put my foot on the gas again and it drives just fine. I'm told it's called limp mode.

Stealership... That's great, I'll be repeating that!

 

[Seth2022]

Request a "ride along" from that dealership. Might take a few more days to get their service manager or whatever a free space on the calendar, but that's what I did for my front output shaft seal. I drove him around and took a route I knew would cause the issue, he heard it, they put it up on a lift, replicated it, and replaced it.

But to Hunter's point, how old is the battery and have you had it load tested for free at Advanced/AutoZone/Etc ? I would assume there's a reason the alternator goes into high output when the brights or wipers are turned on, and a dying battery could probably cause all of these issues.

The hard part about this, i can't get this issue to happen every time, it happens ever ~5th time i take it out. It's not on start up either it's after 15 or 20 minutes of driving.

I can totally see how all power systems are effected by the battery, but how does hitting the brights case all the other system to turn on and off. My whippers come on for 1 up and over, the locks simultaneously pop up and down, tranny shifts, etc. Definitely open to any ideas and I'll get it checked out, but in my head this seems like a circuit board with a bad solder job or moisture damage bridging some copper paths... I failed to mention on the codes in my original post but after I made the video it threw six more codes. One for high voltage control module, one for low voltage control module, abs, traction control, I'll have to find the sheet with the rest.

It's a pretty s***** design for some sort of electrical system design parameter to require a Goldilocks power draw. If that battery is too high or too low.. power steering goes out, thing down shifts, your truck damn near turns off and so on.. this could be deadly at 80 mph on a Colorado highway. To be clear, I'm not saying you're wrong about the battery I'm just really irritated!

 

[ARCowboy]

The hard part about this, i can't get this issue to happen every time, it happens ever ~5th time i take it out. It's not on start up either it's after 15 or 20 minutes of driving.

I can totally see how all power systems are effected by the battery, but how does hitting the brights case all the other system to turn on and off. My whippers come on for 1 up and over, the locks simultaneously pop up and down, tranny shifts, etc. Definitely open to any ideas and I'll get it checked out, but in my head this seems like a circuit board with a bad solder job or moisture damage bridging some copper paths... I failed to mention on the codes in my original post but after I made the video it threw six more codes. One for high voltage control module, one for low voltage control module, abs, traction control, I'll have to find the sheet with the rest.

It's a pretty s***** design for some sort of electrical system design parameter to require a Goldilocks power draw. If that battery is too high or too low.. power steering guess out thing down shifts your truck damn near turns off and so on.. this could be deadly at 80 mph on a Colorado highway. To be clear, I'm not saying you're wrong about the battery I'm just really irritated!

Totally get it man and I have no ego in the diagnosis ! I can be right or wrong, I just hope you'll post up what the fix ends up being so that the next person with this issue can benefit from your struggle.

My guess, which is a complete guess (I'm sorry) is that when you command the highbeams or wipers on, it draws what's called "inrush" which is the initial spike of power. When you draw amps through an electrical conductor, such as copper, you cause heat which increases resistance. Voltage = Amps * Resistance (definition of electrical resistance, commonly erroneously referred to as Ohms law, which is is not). You can play around with online calculators if you want, but if you increase the amps and resistance you have to increase the voltage. A dying battery would be unable to reliably respond with more volts (or would not have the amp hours to support using them more than x amount of time) and thus choke whatever is requesting them for amps.

My complete guess is that you are commanding the BCM to turn on the highbeams, which draw too many amps therefore browning out your BCM and resetting it. It cycles its systems in order to status check them, like wipers, infotainment, tow/haul mode (do you have this ? Could explain the downshifting), and instrument cluster/DIC.

But it could just as easily be a bad ground on the negative cable or broken internal wires. A multimeter and knowledge of DC and electricity would really be required for you to deep dive on the cables/harnesses though. Which you could totally learn, if you had the time/brain bytes available.




For reference, this is the smart charging system operation. All comes down to fuel savings apparently...

Charging System Operation

The purpose of the charging system is to maintain the battery charge and vehicle loads. There are 6 modes of operation and they include:

• Battery Sulfation Mode
• Charge Mode
• Fuel Economy Mode
• Head lamp Mode
• Start Up Mode
• Voltage Reduction Mode

Battery Sulfation Mode

The BCM will enter this mode when the interpreted generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2-3 minutes. The BCM will then determine which mode to

Enter depending on voltage requirements.


Charge Mode

The BCM will enter Charge Mode when ever one of the following conditions are met.​

• The wipers are ON for more than 3 seconds.
• GMLAN (Climate Control Voltage Boost Mode Request) is true, as sensed by the HVAC control head. High speed cooling fan, rear defogger and HVAC high speed blower operation can cause the BCM to enter the Charge Mode.
• The estimated battery temperature is less than 0°C (32°F).
• Battery State of Charge is less than 80 percent.
• Vehicle speed is greater than 145 km/h (90 mph)
• Current sensor fault exists.
• System voltage was determined to be below 12.56 V

​

When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9-15.5 V, depending on the battery state of charge and estimated battery temperature.​

Fuel Economy Mode

The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 amperes and greater than -8 amperes, and the battery state-of-charge is greater than or equal to 80 percent. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5-13.1 V. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.​

Head lamp Mode

The BCM will enter Head lamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9-14.5 V.​

Start Up Mode

When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 seconds.​

Tow/Haul Mode (If applicable)

Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote(non-vehicle) battery will be charged. Having the headlights on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.​

 

[Seth2022]

Totally get it man and I have no ego in the diagnosis ! I can be right or wrong, I just hope you'll post up what the fix ends up being so that the next person with this issue can benefit from your struggle.

My guess, which is a complete guess (I'm sorry) is that when you command the highbeams or wipers on, it draws what's called "inrush" which is the initial spike of power. When you draw amps through an electrical conductor, such as copper, you cause heat which increases resistance. Voltage = Amps * Resistance (definition of electrical resistance, commonly erroneously referred to as Ohms law, which is is not). You can play around with online calculators if you want, but if you increase the amps and resistance you have to increase the voltage. A dying battery would be unable to reliably respond with more volts (or would not have the amp hours to support using them more than x amount of time) and thus choke whatever is requesting them for amps.

My complete guess is that you are commanding the BCM to turn on the highbeams, which draw too many amps therefore browning out your BCM and resetting it. It cycles its systems in order to status check them, like wipers, infotainment, tow/haul mode (do you have this ? Could explain the downshifting), and instrument cluster/DIC.

But it could just as easily be a bad ground on the negative cable or broken internal wires. A multimeter and knowledge of DC and electricity would really be required for you to deep dive on the cables/harnesses though. Which you could totally learn, if you had the time/brain bytes available.




For reference, this is the smart charging system operation. All comes down to fuel savings apparently...

This is great information! I make good money and struggle with free time, so I'm going to swap out the battery and see if the issue resolved. If that doesn't work I guess I'll put my learning cap on.

I absolutely opened this thread up with the intention of posting whatever I find as the solution to be.

 

[Speedy4x4]

Older vechicles I would have suggested like was mentioned earlier, bad ground.
Voltage issues on to many electronics now can be frustrating.
Surprised I have not had issues with the high amo draws I have from compressors and large amplifier, but setup with solid state battery isolators and extra batteries now.
Do you have a pair of jumper cables or some heavy gauge wire you and clean terminals and add a ground and positive lead to eliminate if a issue with ground ir corrosion inside positive lead?
If battery tests good.
Have a manual battery charger, set on 2 amps and leave on for acouole days, not a float charger.


I travel out of state every week, I always carry around a obd Bluetooth adapter ($10) and use torque pro on my phone ($5) has been very handy many times for code reader and the many many gauges it can pull up, maf, all O2 sensors, timing etc etc etc etc
Also on wifes phone and keep a adapter in terrain also.

Sorry for late response, I know how you feel about lack of free time all to well.