Terminal Type ID Terminated Lead Diagnostic Test Probe Terminal Removal Tool Service Terminal Tray Name Core Crimp Insulation Crimp I 13576377 J-35616-35 (VT) J-38125-12A 1326030-8 Lear 17 A 4
Each of the light colored numbers is a number under each of the bold fields.
1326030-8 is service part number for terminal in pcm connector X1 pin 49. it is a type 1 terminal per gm service man.

There are what they call type 2 terminals that are the other size and they may be available but at least in svc manual it says unavailable
For type 2 gives and OE#19330179 says service terminal un availiable
They change that all the time youd just have to check at a dealer I can look tomorrow and see whats out there but you need type 1 so the type 2 isn't important.

Something just hit me 19 was first year for those trucks and 19s are buggy buggy electrical gremlin trucks. We've replaced more than one engine harness on those trucks for a myriad of problems its actually not terribly pricey for the peace of mind it gives. Try changing the terminal first see if it gets you anywhere. I'm assuming by your screen name and tools you know your way around specialized wiring. Fear not they make car stuff out to be way more picky than it is. solder and heat shrink any wires you gotta splice and your golden.

 

https://drive.google.com/drive/folde...XI?usp=sharing
I replaced the engine to cab and cab to frame ground straps. I removed and cleaned every underhood ground.


The Cab to frame ground was also corroded behind the right front fender liner. See the pics in my google drive link above. Before I found the corroded fan ground. I had been looking at an the ecm ignition data on a graph while wiggle testing litterally everything underhood that those ignition circuits are connected to (ecm connectors and fuse panel connectors ect) with hopes of getting the ignition feed to drop out, which I could not reliably cause the circuit to drop out. Its constanly dropping out every like 40 seconds to 3 minutes while driving or in service mode. The only thing i noticed that causes it to drop more often is flicking the Highbeams multiple times.

At the end of the day of inpsecting/testing I noticed the ecm switched ground wire (I think for highspeed) was severly corroded. It was still connected till I pulled on it. How likely do you think this is related to my problem?

 

On computer cars grounds are just as important as power. Where we are corrosion like that's not an issue so didn't suggest looking earlier.
If it fixes the problem then you found the issue is best explanation.

 

I fixed all my problems



Cleaning the fretted ecm connectors definantly fixed my issue.Basically because they put the truck together with no dielectric grease from the factory. The vibration between the unlubricated male and female ECM terminals cause wear, which caused dust to accumulate between the contacts (this dust is only visible in the first close up pic). That dust is the resistance that caused the bad connection when it was cold. I had no issues starting repeatedly for 2 weeks at -20C to -35C after I only cleaned the ecm male terminals and replaced the ECM Ignition relay. See the pics of the brutal terminal fretting. here. https://drive.google.com/drive/folde...82?usp=sharing



I found more issues with my truck bellow which would of caused me to loose my powersteering and brake booster due to my severly corroded ground which had 84000KM (my 2019 just like the video ) on it in the salt belt (theres a bulletin on this)




For anyone that wants to see pictures of the ECM harness MOD I did (reroute so it doesn't wear/ hydraulic hose wrap mod), every ground location in alldata diagrams, the new weather resistant ground straps I made to replace the gm corrosion prone straps and the location of my corroded ecm wire, check out my google drive pics link. https://drive.google.com/drive/folde...XI?usp=sharing



I drilled a few holes in the ecm plastic mounting bracket to feed zipties threw the holes to secure harnesses to the ecm bracket that were previously just wearing on the bracket previously due to the poor routing (its the oem way) of the harness.

The corroded grounds behind the right front fender liner are well hidden as I never spotted them everytime I was under the truck with it on the hoist since owning the truck. Both straps were corroded, Engine to cab and Cab to Frame. See the all data pics for exact ground locations in the link above.



I spent 2 days inside the engine bay with the airbox out, taking apart the ecm harness, inspecting for opens, soldering the coroded ecm wire for ECM switched ground for HIGH speed cooling fan (temporary fix), putting the ecm harness back together properly, securing the harness, so it wont wear on anything. The loose wires inside the harness are now taped tightly together .If I have anymore issues I will be buying a new ecm harness.which is arround 750 CAD.

The problems I noticed with the GM's jackpot ECM/TCM/ FAN harness routing are:

After 4 years of driving, the engine harness cable trays succured to each stut frame mount on both sides of the engine, were unsecured flopping arround with every bump, all the zipties holding the harness to the black plastic cable trays were loose.Meaning the harness was free to move with the cable tray that was free to move. There were rocks between the harness and the cable tray poking at the harness.This didn't seam to cause any damage to the harness, I have not opened that up yet for inspection. I used flange nuts to tighly secure the cable trays to the existing studs from the stut mounts (see in the pic). I used hydraulic hose wrap on the cables in those trays and anywhere there is a jackpot of harness that can wear everywhere. I rerouted the Fan harness from the ecm harness so it can't wear, also secured it to the ecm bracket (made holes in it for zipties).


The octopus jackpot section of the ecm harness next to the ecm was taken apart for inspection. I noticed none of the wires were tighly taped together inside the harness bundle. Which is no good considering that the harness is always getting tugged on when the engine torque raises the engine/flexing the engine mounts, pulling on the harness which is connected to a fixed frame object (ECM).

The fan harness wore on the corner of the plastic ecm mounting bracket. The chaffing from 4 years of driving did not penetrate the tape arround the harness, it caused the loosely danging wire inside the harness to wear and corrode severly a wire which was the switched ecm ground that sends the High speed signal for the cooling fan. (no code for this ever)

The ecm mount seemed quite flimsey/to flexible (maybe so it flexes when the engine pulls on the harness?) which was likely causing more vibration between the ecm and its harness terminals.(possibly why my ecm male terminals were fretting) I used a HD strap pull the ecm down tighter to the frame. Great spot for an ecm, gm will probably save a billion dollars in recalls if there is no data log to investigate for crashes caused by something that would require a recall . The ecm is behind the bumper, it will likly be immidiatly be destroyed during frontal impacts.

I took apart, cleaned and inspected the ecm/ tcm connectors, all other connectors nearby, and applied dielectric grease (since it was assembled with no dielectric grease in mexico) which should prevent any future fretting between terminals. I learned that fretting is caused by not using dielectric grease. Every ground underhood was installed on a painted surface. I removed the paint and cleaned and dielectric greased every under hood ground. After I did all that. While driving, I noticed the OBD voltage is no longer all over the place, no longer noticably lower in voltage than all the ecm ignition voltages and all the ecm ignition voltages are not irratic anymore. The truck cranks a bit faster and I have had no codes or cold starting issues at all now. I will be cleaning the grounds in the cab and checking out the BCM connector pins for corrosion/fretting as salty winter boots are constantly bringing in fresh salt into the cab.

 

 

 

 

Awesome glad you got it all figured out that dang constant wet snow and water corrosion coupled salt or whatever is used up that just ate up everything on that truck alive.