In my Buick there are three ring terminals grounded under the ICM to the ICM mounting bracket studs. I have the ring terminal from the battery ground tail connected to the stud that is closer to the front of the car and the pair of ring terminals (apparently from the harness loom) grounded to the stud that is closer to the cabin. I believe I reinstalled them correctly when I changed the ICM a couple years ago. Now, I’m second guessing myself because the diagrams in the manuals seem to indicate all three going to G100 -- which I assume is the front stud. Any ideas about if I should move the pair of ring terminals forward, or if they belong where they are? Maybe this is of no consequence as the car has been running fine -- until a couple of months ago. I'm making my way through Chart A3.

Thanks Y'all!

BB

I don't have a diagram, but I would say go completely through a reliable diagram and make sure the wires you're seeing are the wires you think they are.

That having been said, if it was running good for a long time, I'd speculate that this wiring isn't the problem.

Any ground to the engine block would be G-100.
You are good.

Thank you!

Well, I have an intermittent electrical problem. Car was occasionally stalling, more frequently it cranked but would not start - no spark. After changing the battery and battery terminals, cleaning every ground, wiggling wires, testing the alternator testing voltages, inspecting sensors, and such -- after getting about 20 different DTC codes after each of two stalls and then waiting for the no-start condition to appear so I could test the ICM signals, verify reference signal, and verify no spark, etc...

After months of nonsense and reading the manuals - yesterday I got a single trouble code on my way to work. #42 Ignition Syst Prob Elec Spark Timing Circuit Fault. For a while, I had been driving around with the sparkplug routing clip bouncing around on the front of the engine. Apparently it was also bouncing on the ICM connector and beat up terminal A & B -- which are in fact at least part problem. Wiggling that little wire kills the engine.

I'm so happy that I bought some tools and the manual instead of throwing parts at it. Next tool may be a metri-pack crimper.

Thanks again,

BB

Good catch, and great news!

Thanks for telling us what you found!