Not familar with JD sabre, but you don't need headlights other than to see with in the dark. You can check the bulbs with a muiltmeter or look for the filment stright broken across the two little prog inside the bulb and there is usually a discolorization of the bulb when it burns out. Head light switch should be on the dash, or maybe they are light them chevies burn all the time? Which is probably why the don't work, maybe the previous owner removed them? If you want to know for sure follow the wires. As far as charging goes it better without lights cause that is a drain on the charging system. Seat shutoff switch is like a light switch either it's on or off and there for your protection in case of roll over or you getting off and you foot sliding under the deck. I would pick up the yard before I mow. I'll let someone else tell you how to do that

Isn't this kind of work fun? The only time you can measure and test for the problem is while it's happening. Any other time that the car actually starts, everything you test will be "spot on" as you put it. Which is a reference to the most likely suspect for your mothers car's symptom. Low fuel pressure I.E. a bad pump. These things will not start with 54PSI of fuel pressure, they must achieve 56PSI! Your gage has to be accurate within 1PSI in that range to actually see this occuring. The thing is, hitting this with a little ether (I prefer propane) will give it some fuel to burn and increase manifold vacuum, and often times allows the car to start, because the vacuum actually helps open the poppet injectors. The poppet injectors are why this thing needs a minimum of 56PSI to start. Other things to consider. "Spark volume" I know you replaced secondary ignition, did you clean the breathers in the base of the distributor? They tend to clog, and then crankcase gasses will collect in the distributor causing corrosion, and then the spark will short to ground inside the distributor. Fuel: It takes more than just fuel pressure to ensure the engine is getting fuel. The injector must be triggered on by the PCM. I have had the two wire connector between the engine harness and the injector corrode and cause a loss of injector command. Plus you need to have a good crank signal trigger to not only tell the computer to drive the injector, but to command the module to trigger the coil. Tell me, when the car acts up. Key on, you hear the pump run for two seconds. Start cranking the engine, do you hear the pump turn back on? This would tell me if the PCM sees the signal from the crank sensor.

Thanks for the input. I replaced both bulbs last night with Sylvania Silver Ultras (on sale). The burned out one had a broken filament for the low beam (high worked). Glass was not broken. Not sure who installed it. I used latex gloves and made sure they were seated tight, wire clamp was secured, the rubber seal around them was snug and connection on good. I didn't feel any vibration while driving. I'm hoping it was just a defect. We'll see. Did an internet search and found many people saying the Sylvanias burned out quickly many times, within 2-3 months many times. I've had them in my cars for 1-2 years now and still working. They liked PIAA, but I think those cost a lot. Thanks for the help.

Has any trouble codes been set? If so, these may give a clue of where to start looking. The other possibility is that the battery voltage might be too low while cranking at cold temperatures. Several electronic ignition systems will fail to fire if the supply voltage falls below 9 volts. If the battery is more than 3 yrs old, or does not have enough cold cranking amps (CCA), it may not have enough capacity to start the engine,