Started normally, stalled, then won't start.

[Erebus]

EDIT. I got it started. See first reply
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Short version:
In -18ºC temperature, it started as normal in that temperature. I drove about 5 feet, and it stalled. Also normal if I don’t keep the revs up. But then it would not start. Not even turn over, just a click of a relay.

I need advice on what might be wrong.

Long version:
Delica L300 Super Exceed, 1992, 225,000 km, bought in 2007 with 24,000 km.
Saturday 19 Feb it was +5. I was helping other ham operators get ready to do radio communications for the “Hypothermic Half Marathon” the next day. While driving around the warning light for A/T temp came on. It has never done that in the 15 years I’ve had it. As per the manual, I put it in park and let it idle until the light went out (a couple of minutes). I check the transmission oil level, it was okay. Drove home, no issues. This may or may not be related.

Sunday, 20 Feb dawns with temperature of -18. The block heater (and battery charger) had been running for a couple of hours. It started the way it normally does at that kind of temperature, without much difficultly, but idles pretty rough. It normally smooths out after a hundred feet or so. (Yes, I should replace the glow plugs, they were new in 2015 at 167,000 km.)

After a few seconds of idling, I put it in Drive and start to leave my driveway. It stalls. That’s not unusual when it is that cold and I don’t keep enough revs on. Put it in neutral, turn the key. Only a click, nothing else. Put it in Park, think for a moment, try again. Still just a click. I figure I’ll try to start it in Neutral, but the gear shift won’t move – the lock button won’t depress, even though I had the brake pedal pressed.

I thought maybe the interlock switch was frozen, since the temperature had dropped so much overnight. I put an AC-powered heater in the driver’s footwell for a while. Then I could shift the gear shift, but still no starting. The dash gear indication matches where the shift lever is. And brake lights do come on when I press the brake pedal (I don’t know if the transmission interlock uses the same switch.)

My voltmeter showed normal voltage. Even so, I put on the big charger that has a “start” function. No difference.

All week, there has been no change. The glow plugs cycle normally, and the glow plug LED I installed a decade ago also lights, but only a click when you turn the key to “start”. I haven’t try much all week, since it has been -10 to -25, and I take transit to work.

The click does not sound like the starter solenoid, it isn’t that loud. It acts an awful lot as if you are trying to start it while in gear.

Has anyone experienced anything like it? Any ideas? Thanks in advance.

[Erebus]

Update on Friday 25 Feb. IT STARTED!!!!!

So for the first time this week, the temperature warmed up to above zero. I just went out, and going on the theory that the transmission interlock switch/sensor had been frozen, I turned the key a bit, then ran the gearshift through the gears from 2 to P a half dozen times, then tried to start it. And it started entirely normally. YAY!

I drove around the block a time or two, and it good.