Mostly how do I stop my vanilla (with no AI mods) self propelled artillery from driving off when it spots an enemy?
I would have thought putting this setfuel 0; in the code section of the module would work. I also tried this disableAI "AUTOCOMBAT"; and this disableAI "PATH"; but they still wander off and get themselves assploded.

Please help me save the lives of my poor dumb arty guys so they can murder innocents with indiscriminate shelling of civilian locations. (Don't tell the IDAP) :(

I just surround them in H-Barriers. I think it'll keep them in place as I've never seen mine drive off since I've started doing that.

If you select the driver of the vehicle and disable move for that soldier it's worked for me in the past.