Random no power no start

[Gord Rule]

Recent random problem on 2015 Sierra 1500 5.3l.

Drove to store. Locked truck with fob.

Returned unlocked with fob.

Inserted key.

Nothing

No lights no dash no power whatsoever.

FOB not working anymore either.

Popped hood to check battery cables.

All good.

Tried fob to lock unlock.

Now it works.

Closed hood.

Truck starts and all is fine.

Stopped at home driveway.

Did it again.

Open and closed hood to fix.

Already tested hood latch resistances.

Within tolerance numbers.

Any Ideas?

Edited July 31, 2025 by Gord Rule

[mikeyk101]

Are you possibly using an older Range AFM disabler in the OBDII port?

Edited July 31, 2025 by mikeyk101

[Gord Rule]

No I am not.

Thought about using but haven't yet.

[mikeyk101]

I brought that up because I suffered a no start issue with mine. Dealership decided bad starter and replaced it. It happened again a few months later and accidentally discovered that it was the older Range Disabler after truck started when the disabler was removed. Range swapped it out with updated version and haven't had that problem since. Hopefully you are able to make some progress on your issue.

[Gord Rule]

Thanks for the info man.

At this point i wish that was the problem cuz right now I don't have a clue.

Taking it to my mechanic this afternoon to scope it. 

Hopefully it will tell us something.

[Gord Rule]

Well yesterday it happened again.

No start

No power

Not anything.

This time i had to disconnect battery.

I left it for about 30 mins. and retried.

Back to normal again.

Booked it in to GM dealer but won't be looked at for another couple weeks.

Short trips til then and i won't be turning it off til back in driveway.

It sucks not trusting your wheels.

[rav3]

Check the top of your battery Power Distribution unit. I've seen where the nuts will work loose on a power lead & cause this issue. Make sure they are all tight.

[Gord Rule]

Thanks for info.

When pulling off cables for the reset I did notice some corrosive residue around and on the steel plates that the terminals are fastened to.

Not real bad like rusted through or anything but wondering if enough to cause electrical confusion?

On previous inspection I did remove positive cable from this area and clean up but not the remainder.

I'll revisit and clean and check for loose connections.

[rav3]

watch this video

 

[Gord Rule]

I checked the video out.

Yes that is the area I'm looking at.

I'll check and clean.

Thanks man

[Gord Rule]

Update: Local GM dealer scanned my truck but couldn't find anything definitive on the no start issue.

Did however find a code b1370 - control module ignition on run/start circuit open.

Did circuit testing for ignition switch and found all live data within spec.

Tested for shorts to ground and power through connector, tested resistance from switch to BCM.

No problems with circuits.

Does however recommend replacing ignition switch.

I have ordered switch but as of yet not replaced.

Hoping this will solve issue.

Time will tell.

Any comments?

Thanks 

Gord