No crank no start?

Hello Joe. Thanks for reaching out to me.

Damaged and melted was the black (ground) wire coming out of the ECM. I replaced it with a new wire (same gauge) and grounded it in back of engine... Running to the same pin as the fried wire.
When I tried starting it from the ignition, there’s power but no crank or click. When I bypass the ignition through the fuse box crank relay connections, I get a click. It did turn over doing that earlier, but now it’s back to just clicking again once, with each repeated attempt.

There are other electrical components working, like the lights, exterior and interior, radio, etc. Previous to this challenge, I was experiencing the engine overheating (at least the car’s computer was alerting me of that fact). Previous to the overheating, the vehicle stopped blowing hot air (started doing that a couple years ago or so). That got worse and worse until the overheating started taking over this past year. I bypassed the heater core, and the vehicle stopped overheating. I was slowly losing coolant before, as it seems it was not getting past the heater core or something, filling my vehicle up with coolant smell and getting that film on the interior windows? That made the coolant get low, I do believe, but now it’s staying pretty level, though I haven’t had the vehicle running in almost a month.
-Ron

Is this working? Okay, I would like to take the back metal panel off of the PCM to examine it for burn marks. What say you?
-Ron

Hello. Here’s what I found out at a shop I had my vehicle fixed at $1,200 later.

Eng: 3.4l, v6 (209ci) vin(f)
Description of services
No crank no start - thinks it is electrical issues
Verified the customer's concern of no crank
Checked the gm service information for technical service bulletins, recalls, special coverage, and service updates
And found no documents related to the vehicles concern
Pushed vehicle inside, raised the vehicle and performed a visual inspection
Accessed the diagnostic port and performed a scan which found code is related to loss of communication and then
Cleared all codes and reconfirmed active diagnostic trouble code(s) for loss of communication
Performed strategy-based diagnostics
Tested the PCM, TCM wiring both power and grounds
Found customer ran ground wire to PCM. TCM has no communication as well traced back result of customer ran
Ground wire. Found burnt wire. Replaced burnt wire to and from the PCM, this was the same case for the TCM, and
Immo module. This disabling the engine from starting. Repaired wiring, and attempted communication. Found 2
Blown fuses. Reestablished communication. DTCs would then clear. Vehicle still would not start. Found that
Calibration has been cleared from the ECM. Performed ECM programming. After programming found that the vehicle
Now starts and dies. Communication was established with the immo and found that it was in anti-theft protection.
Performed immobilizer relearn, vehicle started and ran. Noticed coolant leak when engine was running. Upon
Inspection found that the radiator was leaking pretty badly. As vehicle continued to run found that it was
Starting to idle poorly and noticed that there was a vacuum line disconnected on the back of the engine.
Reconnected vacuum line and reset fuel trims. Engine idled well. Parked vehicle outside. Next day went out to
Vehicle and it was dead. Had to be jumped. After giving jump start, vehicle started. Tested battery and battery
Failed. Recommend battery.
Labor: $1,317.50 hrs: 8.50
Description sale extended
Quantity
Relay 1.00 $17.90 $17.90
Parts: $17.90
Sublet:$0.00
Job total: $1,335.40

1/10/2025
01/08/2025 radiator - remove & replace

Now, today, my temperature gauge seems to have stopped working (just sits at low and doesn’t move) and both radiator fans stay running all the time while vehicle is running. Display instrument information panel shows engine hot a/c off and service tire monitor system, check engine light is on and (blinking) yellow exclamation point is on.