How To: Strange electrical issues with 14-18 Sierra/Yukon? Do this test first!

[rav3]

5 hours ago, tlaw91 said:

Keep both feet depressed on the pedals when cranking.

 

Let off to get out of clear flood.

 

This post is about bad battery cables and how to test them.

 

I’ve never seen bad dash grounds. Never fixed them. And I work on 5-10 vehicles a day.

 

There is no body ground near the starter.

OK tlaw91.....to clarify my comment about the ground down by the starter, I'm referring to the (2) grounds that are mentioned in the below video....Passenger side, ground to body.

2014 Silverado no crank no start problem solved!

 

On the dash ground(s) please watch this video. I think GM finally fixed this issue on later truck but lots of Chevys had this issue. (Both sides)

2014 Chevy Silverado electrical issues and Stabilitrack issue FIXED!!!!

 

A bad ground will cause ALL kind of electrical issue, from no start to all the other little gremlins. Just like an old or bad battery AND bad battery cables as you mentioned. Some people have even gone to adding additional (heavier cables) grounds. Always use dielectric grease to all electrical connections when you have them disconnected.

 

Hope this helps clarify my questions. Again, thanks for your post. It's good info.

[tlaw91]

Dude had a rare issue on the early 14’s.

I’ve never seen it/never had it fix anything.

Please avoid using dielectric grease for anything other then spark plugs.

If you must use something use dielectric lubricant. Mostly used on micro 64 and micro 50 connections for terminal fretting issues.

[tbarn]

Delco p/n 10-4064 grease for high temps and voltage. Think spark plug boots.

Delco p/n 10-4071 lube for low temps voltage. Think 12 volts and less.

 

 

Edited December 12, 2020 by tbarn

[Darksky]

Replacement cables? Are there heavier gauge, finer stranded, more insulated, higher quality connector type cables to be had? Which ones, exactly do you recommend? The variations in different brands and caliber of manufacturers is like anything else, they vary wildly. Which cables should I Buy for my 2015 L86 High Country? Please and thank you.

[tlaw91]

Replacement cables? Are there heavier gauge, finer stranded, more insulated, higher quality connector type cables to be had? Which ones, exactly do you recommend? The variations in different brands and caliber of manufacturers is like anything else, they vary wildly. Which cables should I Buy for my 2015 L86 High Country? Please and thank you.

Factory cables


Sent from my iPhone using Tapatalk

[BlaineBug]

8 hours ago, tlaw91 said:

Factory cables


Sent from my iPhone using Tapatalk

If you wanted you could always have a replacement set of cables made with proper crimp connections rather than doing it the 'ol shadetree mechanic way.

[tlaw91]

I just install new factory OEM cables

I also don’t check them anymore I just replace them. Way too many issues with them

[C Dave]

Thanks for posting these repairs tlaw91.  I look forward to this type of insight. 

[2018GMC]

My neg cable didn’t even register a DC mv reading. My pos cable was 5.53 with a jump to 11.65.

 

Got a low battery alert which also notified onstar? after doing this test. I got an diagnostic email lol. Battery voltage is 12.62 so maybe my battery is weak? Or my random service stabilatrack message is a different issue.

[tlaw91]

My neg cable didn’t even register a DC mv reading. My pos cable was 5.53 with a jump to 11.65.
 
Got a low battery alert which also notified onstar? after doing this test. I got an diagnostic email lol. Battery voltage is 12.62 so maybe my battery is weak? Or my random service stabilatrack message is a different issue.

None of what you just said sounds like you did the test correctly?
But if you cranked your truck for less then 30 sec then you got a low battery message then you need a battery ASAP

[BlaineBug]

On 12/19/2020 at 4:25 PM, 2018GMC said:

My neg cable didn’t even register a DC mv reading. My pos cable was 5.53 with a jump to 11.65.

 

Got a low battery alert which also notified onstar? after doing this test. I got an diagnostic email lol. Battery voltage is 12.62 so maybe my battery is weak? Or my random service stabilatrack message is a different issue.

Check the ground connection on the frame, behind the passenger side front wheel, beneath the wheel liner towards the bottom. You can just hold it back. Requires removal of nothing if you turn your steering appropriately.

Remove the ground bolt, clean up the mating surface, put it back, and try that for a little while.

[2018GMC]

1st pic was what it looked like from factory after I removed 10mm bolt and neg cable. 2nd and 3rd pic after I wiped off wax with a paper towel. 
 

Will have to give it a few days or weeks to see if I get service stabilitrack message again. 

[BlaineBug]

Nice.  I wire wheeled the mating surface on my Yukon, then painted it once reassembled.  I did a better job than the dealer tech did which is why I investigated this after receiving back from the dealer.  So my problems were either THIS ground or the ECM as both were dealt with simultaneously.

 

For you it is worth a shot.  As far as I know the G218 ground issue in the upper dash with insulation being pinched between the wire and vehicle body was dealt with and potentially only affected 2014-2015 and possibly 2016 truck models only.

 

However if you wanted to double check G218, feel free for your peace of mind.  There are aplenty write ups for that one which show exactly where it is.

Edited December 23, 2020 by BlaineBug

[2018GMC]

Here is the TSB with the voltage drop test, Dash grounds G218 check, and starter heat shield shorting out on starter solenoid positive cable.

 

https://static.nhtsa.gov/odi/tsbs/2019/MC-10168185-9999.pdf

Edited January 7, 2021 by 2018GMC

[2018GMC]

Update: cleaning the wax off frame and negative cable didn’t solve the random service stabilitrack message. Still had a month of warranty left so took to dealer. They replaced negative battery cable due to high resistance. Hopefully that solves it.