You need to take a step back and look again at the hook up of your ICM.
I agree splices are where you get a lot of these sudden issues but you need to unplug your ICM module and have a look at what you have on the plugs coming in from the harness.
The test light is invaluable but you also need a multimeter to check the sensor.
On the 2 pin plug do you have battery voltage on the Red wire in Run and Start and on the White wire in Start only? This is the power to your module.
On the 4 pin plug have you got a ground in your Black wire? This wire runs back to the dizzie and grounds through there and is often the issue. The module does NOT ground through the case.
The green wire goes out to the coil -ve. Check it is elctrically continuous.
That leaves the two sensor wires, purple and orange if I recall, you should have 500-750 ohm resistance between those wires. If you are Nutterring make sure you have this level of resistance and have not switched the wires over, it will start switched but backfire immediately.
If all that is correct it SHOULD work. I have had shorting plugs, wonky earths and once a burned module.
BagusJeep lives in Bali.
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE