So it turns out that she said when it died the radio and gauges all died for a moment and then it wouldn't start. I need to check all the fuses in the morning.
1. If the radio and gauges all died and it wouldn't start, you could have a problem with "grounds". Freshen them. Don't want to be chasing your tail for a simple ground issue. More on freshening grounds below.
2. Get us that code number as it may be important here. We need the
EXACT number, not just the circuit it is related to, as with OBD, the devil is in the details. Can't ever ignore codes, as your Jeep is trying to tell you something and it could easily be related to your symptoms.
3. When you check for spark, you must have a strong,
blue, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea!
You can't just check or look at these grounds. You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. The one on the back corner of the head, and where it attaches to the firewall. Scrape the paint from the firewall. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.
Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.
If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support. Scrape the paint off first.