Now that's a new one I've never heard of.

Along Bill's train of thought, hope you checked the battery ground connections at the nearby frame member and as well at the block. Loosen, clean if needed, De-oxit if you have it, and re-tighten. Double check that the battery clamps are well seated on the posts and properly tight -loosen, twist down, re-tighten. Inspect the battery cable clamps and all crimp connectors at the other end of both battery cables for signs of corrosion or broken strands. Are any of those cables or clamps aftermarket? You could measure voltages and voltage drops in the charging system, but I'd keep tend to skip that for now as you're symptoms are rather sudden.

If that doesn't make a major difference then you need to start thinking harder, like a possible short somewhere or a ground fault causing an alternate path to ground.

I'd start fault tracing from the errant stalk switch by isolating various parts of the circuit. I'm looking at the GB version of the 900 high and low beam circuits -should be the same or similar for all 900s.

Begin by pulling the headlight relay, relay tray, front row, second socket from the left. That eliminates any stray 12V getting from the battery to the bulb out sensor relay and beyond to the headlamps and their ground. It also eliminates any chance of 12V passing from the stalk switch to ground through the high beam relay to ground. Re-test for stalling. If that fixes it then that relay, the stalk switch and associated wiring goes on the chief suspect list and you begin further isolating from there.

If no change then with that relay re-installed, pull the high beam relay, front row, rightmost socket. That elimnates any voltage from battery +12V getting to the headlamps through fuses 17 & 18 and as well the high beam indicator on the dash. Re-test. If that fixes it then that relay and associated wiring, especially at the headlamp grounds and under the relay tray goes on the chief suspect list.

While we're on that part of the circuit, check the headlamp socket connectors. If they ever make poor contact then the contacts get hot and the plastic can melt, allowing the wires to pull out or short (I've had one such problem with headlamps occasionally going out). DRL means current is always passing through. Those connectors are an even bigger issue if high intensity lamps are used.

If neither makes a diff then the stalk switch goes on the suspect list and as well a possible ground fault some place in the engine management system.

Report back and we can take it from there.

A couple of questions:
o When you touch the stalk and stall out, is it a sudden stall or does it begin with a stumble or misfire?
o If only the park lights are on (headlight switch in the middle position) does that change things? I believe your DRL light switch is the same as mine and operates that way.
o Does the high beam dash indicator light at the same time?
o Does the intensity of dash lighting change (turn up on high when checking that)?
o With headlights on, does the intensity of the beam suddenly drop (go up against a wall)?
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now