Just looked in my 1987 240 Owner's Manual, page 17.

Looks like the 1987's are the same as the 1986, which I drive.

Rocker switch horizontal below headlight switch is the control. It is lighted when the fog lights are on. No power to switch or lights unless the headlights are on low beam.

If the switch doesn't light up when you think the fog lights are on - look in the back and see if they are on. The little bulb in the switch goes bad after 19 years or so. Bulbs are available at AutoZone or other corner parts houses.

Good LUck,

Bob

:>)