My "check engine" light is on so I pulled the codes on my '91, 3.9, auto. Dakota. Came up with: 12: low battery 36: different definitions 37: solenoid coil circuit 41: alternator field circuit open (?) I know that my ammeter gauge is registering just above the second hash mark (where 12v would be) At one point, it was halfway up the gauge (around 14-15v), even at idle with AC and headlights on. What should I be looking at with those codes? I do NOT want to get stranded with a bad alternator/dead battery.