Here's the history...

Late November From I stop at a stop light, I accelerated. The car shut down (all lights (including the lights on the instrument panel) and the engine). I put the car in neutral, and while coasting, I started the care. It ran for a few seconds, enough to get me out of the intersection completely and then it shut down (all lights and the engine). I opened the hood and looked at the battery. The positive cable seemed a bit loose. I rotated it a bit and the car started up immediately and I drove home without incident. At home I tightened the positive battery cable.

Early December When driving to work, my battery light illuminated. It would go off when I ran RPMs over 2K. That evening, after work, shut down again and I was stranded on the side of the road. As opposed to the event in late November, I could use my flashers (thankfully) but I could not restart the car. I was towed home. The next day I replaced the battery and the alternator. The car worked fine since then.

December 22, 2013 I drove the car for 1.5 miles this morning. It worked fine. After 4 hours, I came back to my car and found that I could not start it. I could not even hear the click from attempting to start it. It seemed to have no lights (including lights on the instrument panel). I tried to jump it with a car, but it would not start. When I attached the jumper cables, the instrument panel illuminated and when we attempted to start it, we could hear more clicking from the starter, but it would not turn over. I abandoned the car for the night.

December 23, 2013 I used a fully charged jumper box and the car started up immediately. But I noticed the airbag light on the instrument panel was illuminated. It has never been illuminated over the 15 years that I have owned the vehicle. I drove the car 1.5 miles home. After 2 hours, when I attempted to start the car it would not start. I figured the short drive did not charge the battery enough. So I pulled out the trusty jumper box and the car fired up just fine. I drove it for about 1 hour around town without turning it off (so I could charge the battery). After turning off the car, the car would not start again. This time, the instrument panel would light up just fine but there were no clicking or other starter sounds when we tried to start the car. I happened to be at O’Reilly’s Auto Parts store (to buy a battery charger) and the manager there tested the battery as fine. We replaced the starter relay switch but nothing changed. The tow truck driver came and sat in the car and started it. I asked what his magic trick was and he said the neutral start control (or something light that was tripped). So he said to turn on the ignition, put the car in neutral and then attempt to start it. When he did so, the car fired up just fine. He turned off the car and started the car normally a few times. The manager tested the battery and the alternator again and they both tested just fine. The car may be fixed, but I have my doubts. The airbag light is still on. Of course, I’m worried that I’ll get stranded somewhere. I need your best minds to help me figure out what you think is going on.

Is this a neutral control switch or relay?

What about the airbag control light? That's odd...

Welcoming your comments.

 

Welcome to CL as a new poster.

This is a tough one (and tracking intermittent electrical shorts/problems can be very difficult with the complex electronics in today's cars). Right off-hand, though, it sounds like the tow-truck driver may have a clue......something in the Neutral/Park starter relay may be allowing the vehicle to start in Neutral but not in Park. There may (?) also be in intermittent problem in the alternator or ignition coils that either does not charge the battery properly or supply enough current to keep the spark plugs firing and the engine running. Last, has a technician scanned for any CHECK ENGINE codes? If a code is found, the proper way for the technician to deal with it is NOT to just knee-jerk replace the part the code indicates...that nay or may not solve the problem. The proper way is for him or her to record the code, consult the factory Repair/Service manual for the car/engine, and THEN do the required tests indicated by the code.

 

Welcome to CL!

I like the idea of the neutral switch, those things can fail. A couple of other ideas that might deserve investigation before you go into the expensive stuff:

Battery terminals, particularly on the clamp (or bolted) side. may be corroded. Clean terminals with a wire brush and treat with a solution of baking soda in water to neutralize acid wicking up the post from the battery. Wipe clean with a dry rag and put a little light lithium grease on the connection. Living as you do in Florida where humidity is high, you might invest in a couple of those felt battery terminal pads to slip over your battery connections. These are commonly used on marine batteries where moisture is always a problem. Soaked with a little oil, they will usually prevent battery acid from attacking the connections.

Battery connections can be tricky - your interior lights, even your headlights may work just fine, but when you ask that circuit for a heavy draw like the starter, it can't supply the amps because there isn't enough contact there. That kind of failure can upset a lot of stuff in your engine and body computers, maybe accounting for that airbag light.

Here's a weird one I just found a couple months ago. My daughter's older pickup was having much the same problems, but the battery seemed to be good, the connections tight, and the accessories working. The engine would turn over but simply wouldn't start. We'd just put in a new fuel pump, and it seemed to be working fine, but starting fluid (ether) sprayed into the carburetor wouldn't produce a single pop. The ignition system seemed to be dead - although it was fairly new. Fuses and relays seemed to be good, but the stupid thing would run just fine for a while, then quit. It would take anywhere from 20 minutes to three weeks, but the engine would die without warning. Usually in traffic, and usually precipitating a frustrated call from my daughter. Most of the time, just sitting for three or four minutes would restore the ignition and she'd be on her way again. Of course it never failed in our driveway and there was nothing to test.

Long story shorter, I'd overlooked the fact that cars (and obviously, trucks) built since the early '70's have a mandated "kill" circuit that will disable the engine in case of a crash. Normally they will interrupt the ignition, but may also shut down the electric fuel pump and injectors - in some cases, even the starter - as a belt-and-suspenders approach to the problem. In a collision, you want to be dead sure in case of a fuel spill the engine is off and the fuel pump is not supplying more fuel to the potential fire. Most of the time this never presents a problem - the technology is basically of the Flintstone's era, and aside from a little relay in one of the fuse blocks, there are really no service points in it.

Well finally one morning it wouldn't start in our driveway. Desperate, I swapped the relay (the AC clutch relay is identical on her Dakota), but no luck. Two days at the local garage tracing down the problem, we found the ground wire to the relay had been connected to a mounting screw UNDER the fuse block at the factory, and it had corroded. The relay was intermittently being disconnected - and being a normally open-contact that depended on the presence of 12v to close it and energize the ignition system, it dutifully shut it down. A little wire brush work, a new wire, and a bolt through the inner fender, rather than the OEM sheet metal screw, and all was well.