truck died and won't stay running

[Smeastman]

2019 Sierra sle 5.3

Saturday morning I pushed the start button on my truck and it just went "click", sounded like the starter engaged but not enough battery to turn over, I was in a hurry to get to an auction to ironically bid on a car hauler so I grabbed a different vehicle. Got out bid on the trailer, came home through a jump pack on the battery left it for about 20 minuets, truck started all seemed good, no warning lights no other symptoms. I drove down to a local pizza joint to pick up some wings and pizza out of habit turned the truck off when I got there, when I went to leave push button and "click". a guy I knew was there, tried to jump the truck, same thing "click", called wife, she came down with my good cables put them on for about 15 min and the truck pops off, down the road we go, about 1/2 mile from home dic says "service charging system, truck may stall" and it did. jumped it again, it stalls about 20 feet down the road, towed it home. Voltage on the battery measured 12.4vdc and stayed the same when I pushed the start button, put it on the charger at 50A for 30 min battery measured 13.6vdc, truck starts all looks normal. while its running I start to measure voltages, at the battery I measure 14.0vdc, at the alternator I measure 14vdc, from all points on the power distribution center on top the battery I measure 14.0vdc, about 20 min in it dies again. replace battery with fully charged battery, same story. Any suggestions?

 

sorry so long.        

Edited October 5, 2023 by Smeastman

[Bikerjon]

I would check the alternator output. Load it with a charging system tester and measure amperage output or take it to a mechanic who has a charging system tester.

[Transient]

Iirc, autozone is able to test alternators.  Other auto parts stores might be able to, too.  Might be worth calling a few in your area to see if they can test your alternator should you take it to them.  

[Smeastman]

Up Date; after much digging and troubleshooting found the problem. the wiring harness to the ECM was wore through and the main power wire to the ECM was broke. I'm not sure how the truck was starting with a jump or fully charged battery the few times it did but after repairing the wire it starts and acts just like its support to.

[MrMagloo]

Seems these trucks exhibit an unusually high number of chaffing issues.

[Mshawn]

On 10/16/2023 at 2:29 PM, Smeastman said:

Up Date; after much digging and troubleshooting found the problem. the wiring harness to the ECM was wore through and the main power wire to the ECM was broke. I'm not sure how the truck was starting with a jump or fully charged battery the few times it did but after repairing the wire it starts and acts just like its support to.

Where was the harness problem located at in the engine bay? I’ve noticed there has been more than a few problems with wiring harness chaffing