Possessed Headlights on '96 Q45

[soloQ45]

My 1996 Q45 has a possessed headlights.
When I turn the headlights on, occasionally (2 out of 3 times) only the high-beams come on...and the all the lights in the dashboard go off....and the tail lights go off.
After about 5 minutes, the headlights revert to normal, the dashboard lights turn on and the tail lights also turn on.
If I turn the lights off, the whole things repeats itself. It's like turning the lights off "discharges the circuit" and it needs to re-charge.
Please don't tell me it's the switch in the steering column...from the looks of the shop manual, that's a big deal to replace.
I've checked the fuses. Maybe the relay...How do you check a relay...especially when the problem's intermittent?

[qship96]

how many miles on the car? How long have you owned it?

[soloQ45]

169K, 10 years

[goody90q45]

Any warnings in the odometer display? Pull out the brake lamp modules (no tools required) and look at the bulb sockets and the receptacles in the modules. Any signs of melting, charring, or burnt wires? Replace dual filament bulbs with long life (LL) bulbs. Sylvannia is best.

Have you replaced any of the micro bulbs in the interior lately? I burnt a fuse installing a bulb (using a metal screwdriver with the lights on) and had the same symptoms- high beams and tail lights only and none of the interior lights worked. Check the ILL (illumination) fuse with a voltmeter or magnifying glass or swap it with a like fuse to verify it's good.