Unresolved electrical issue, truck unsafe to drive.

[Cooper Rictor]

Hello,

I’ve been trying to resolve an electrical issue with my 2014 Z71 LT 5.3V8 Silverado completely shutting down electrically/mechanically while driving or parked, it’s been almost 1.5 years now. The dealership has not been able to help due to the issue not happening when they diagnose. I have racked up thousands of dollars in car rental and diagnosis fees trying to resolve this. I have seen bits and pieces of my problems through this forum but nothing specific to lead to a fix, would love some advice after I get through all this. The instances are very inconsistent and unpredictable, so I’ll just list out a timeline of what has happened, I have never had a check engine light:

 

-          (Roughly 2 years ago after years of perfect operation) While driving I get a momentary electrical blip where all electronics quickly turn off/on, I then get errors for stabilitrak. Once I get into city traffic I notice some resistance in steering, while pulling into a parking spot I get full engine shutdown and the steering wheel locks. Electrical systems cycle and I can restart the truck. Sometimes when this issue happened, I couldn't restart immediately, after a wait I could start the truck. This issue always starts with an error message usually after driving for a while, so it looked like something related to heat.

 

After this issue my truck spent two weeks at the dealership where they could not replicate the issue, and nothing was resolved. I read about the grounding issues and decided to investigate myself because the dealership wasn’t willing. The G218 ground under the dash WAS impacted by the sound deadening material so I trimmed it away and ensured a solid connection. The ground behind the passenger side wheel well was corroded slightly so I cleaned the connection and ensured it was tight and secure.

 

*Fast forward 6 months, the previous issue had stopped completely*

 

-          The current issue started as a momentary electrical blip while driving and then a stabilitrak error message. Once parked, I turn the engine off and when I open the door the electronics click off normally, but instead of just turning off the instrument cluster and radio the truck is completely dead electrically, not even hazard lights. After a while power returns and the truck can be started normally. The dash clock resets to 1200 and all sensors reset, it took me forever to finally pass emissions by not having a loss of power for at least a week so I can get the mileage in so the sensors will be active for the emissions test.

 

-          Sometimes when attempting to crank the engine there will be a brief studder/pause and a theft deterrent system error message appears, the truck still starts up but there is the theft detection light on in the dash. When this happens the issue of losing power when you turn off the engine and open the door happens every time.

 

-          Sometimes when remote starting, the truck attempts to start but instead clicks like there is a dead battery. When I open the door, the truck is dead electrically. Power returns after a short time.

 

-          While exiting the highway and slowing down for the light the engine completely shuts off. The Steering wheel did not lock, and no error messages were called out. I shifted to park at the light and re-started; I did not lose electrical power when I left the vehicle.

 

-          While driving at a slow speed around town, I made a turn and the engine and electrical power shut off completely. The truck was completely dead electrically/mechanically, I coasted and was able to get to the side of the road. There was nothing electrically, not even hazard lights.

 

*These instances have started to happen more and more frequently as the months progress, the frequency is definitely more common when its hot out as opposed to winter driving.*

 

*My findings and what I’ve done: When losing electrical power months ago, the power would return after a little while. This transitioned into me needing to remove the negative battery cable and reconnecting it to have power return, I know it works when I hear the little zap when the cable touches the terminal. Now, currently, when the power issue happens power does not return immediately after reconnecting the battery cable. When I touch the cable to the negative side there is no spark, so I let it sit and try every 20 min. I was stranded on the side of the road for 2 hours this weekend, when the tow driver showed up, I tried the cable again and sure enough, it sparked, and all power returned. I was able to drive home.

 

What I have done: I went to the dealership again, they pulled codes and said there was a ton of low voltage codes. They told me it must be a bad negative battery cable. So, I went home and removed the negative battery cable; the cable looks perfectly fine, the connection ends are clean and un-corroded, the cable rubber is not cracked/blistered or marred, the shrink wrap at the connection ends is rock solid, the heat wrap is clean and intact, the rubber under is perfectly clean. The impedance check from battery terminal end to each other end is the same and low impedance. I opened the main fuse box under the hood and the driver side fuse box by the instrument cluster. There is no signs of moisture or corrosion, all relays are secured and look new. Just visually inspecting my truck everything is very clean, almost new looking. This truck lives in a garage.

 

*Like I stated above, none of the above issues can be predicted or anticipated. It will be weeks of perfect operation and then a sudden complete engine/electrical cutoff randomly. This is so frustrating when having a dealership diagnose the issue*

 

Ok that’s the wall of text. I’m at a point now where this vehicle is unsafe to drive, I have two choices: sell it off to a dealership and take what I can get towards another vehicle or submit it back to the dealership mechanics and rack another $1000 in car rental charges hoping the issue happens when they have their computer hooked up. I own this truck completely and its very clean and well taken care of, I want to keep this truck. Any advice would be appreciated. I can answer any questions you have.

 

Thanks for your time.

[64BAwagon]

Hopefully someone will chime in that is a tech with good diagnostic skills. I have background in electrical diag on vehicles but dont have GM training which is likely someone you will need. 

Having said that the first thing I would do is replace the battery (if its newer than the problem I would skip this)  and both the pos and neg cables, no matter how good they look. The battery could be shorting internally. The cables are almost always the #1 suspect no matter how good they look. 

Next I would pull the underhood fuse box apart and start looking for loose or damaged connections. After that start poking around under the dash and pull testing items and looking for abnormalities. 

I had an S10 in the 90's that did the same thing. It ended being towed to the dealer twice (under warranty) because it just quit. I ended up figuring it out myself the next time it died. I wiggled the ECM fuse under the hood and it fired right up. The fuse receptacle in the box was sloppy, all I had to do is slightly twist the 2 fuse legas and the truck never skipped a beat after that. 

 

Good luck. 

[UrbanRage]

It sounds like a loose connection. Before I started throwing parts at it, as 64BAwagon recommended, I would verify connections are tight and there isn't any corrosion on the underside of the fuse box under the hood. I would also check the connections on the fuse box located on the driver's side dashboard, and the relays just below the fuse box. If everything checks out, I would look into the battery, cables, and possibly the ignition switch. I hope this helps.  Good luck.

Edited July 13, 2023 by UrbanRage

[rlcole321]

All good suggestion, one thing to note is although the Batt. cables may look good on the outside, there can be significant corrosion on the inside, that can't be seen easily from outside inspection. Look at the outside insulation closely or run your fingers down the cable and feel for "Bumps", this would indicate possible internal corrosion. you can also try a voltage differential test, take a volt meter, put the Pos. lead on the battery, and test different "Battery Power" fuses or any non-relay controlled batt power points (use a good jummper wire for length if needed) using the Neg. lead. There shouldn't be more that .5 volt difference, if you see 1 or 2 volts difference, then there is a connection problem. Might help??

[sk]

There is an entire bulletin about bad grounds.  Look up PIT5405 (I don't know what version is the latest).  The G218 ground is part of it, and so are the battery cables, but it also lists a long diagnostic procedure for other areas (like an arc near the starter).

 

There are also other grounds to check that aren't listed in that PIT.  For example there is one in the passenger front wheel well, and some underneath near the body mounts.  If you search these forums and YouTube it will come up with a bunch of hits.

 

And as others have said check the battery itself and all connections.  I went through all of this and it solved most of my problems, but I actually had something happen years after that and thought I was going to have to go through all this again.  Turns out the mechanic had the battery disconnected to do some unrelated work but didn't tighten the cables ....

[14LTZ-1LZ]

PIT5405C.pdf

[crueski]

On 7/12/2023 at 5:06 PM, Cooper Rictor said:

I've had several of the same issues you are describing, i recommend replacing the negative battery cable, no matter how good it looks on the outside.