Superformance lights coming on after washing?

[Blas]

The lighting circuit includes a dash toggle switch, a headlight latching relay, indicator stalk, dash gauge lighting, F&R parking lights, some fuses and of course the two front headlights.
The dash lighting and parking lights are powered thru the dash toggle switch’s first position.
The headlight low beams are activated thru the dash switch’s second position.
You should be able to flash the high beams with the stalk switch with the car on or off and the headlights on or off. Next time they are stuck on, try flashing the high beams, see what happens.

Which headlights are coming on after you wash the car, low beams or high beams?
Are the parking lights also on? - I would guess not.
Dash lights also on? - I would guess not.
I'm guessing it is your high beams that are coming on....

The dash lights would have no discrete power source associated with them other than the dash toggle switch, so I would rule them out as related to the problem.
Same is true for the parking lights.

To illuminate the low beam headlights, a power signal would need to be routed thru the headlight's latching relay from the dash toggle switch.
The stalks momentary ground switch adds the high beams to the front low beam lighting.
The latching relay has a full-time power source, it is just the internal latching switch needs to be activated inside the relay to get high beams.
The stalk has a momentary ground to activate the high beams but the high beams still need the relays internal power source to operate.

What have you replaced in the lighting circuit to date?
Trace the lighting circuit on my wiring diagram if you have one, really makes it easy to understand. If your high beams are activating, it must be related to the stalk via the intermittent ground. You could unplug the stalk under the dash wash the car and narrow the problem down further.

Next time the lights go on after washing, check to see if you have + power on the #56 post on the headlight relay. Power would need to be coming from the dash toggle switch if you do. or an internal relay problem.
You could also disconnect the "S" terminal on the relay which will take the stalk out of the equation and see if the lights go off.

Blas