I'm with hardknocks.

That is, could be the relay. It has multiple components internally, and two internal output contacts - one for the OD light, one for the solenoid. Quite possibly the contact for the light is dirty etc. and has quit working. Or some other internal mechanical or electrical conductivity issue is disabling the output to the light, and the output to solenoid is still working.

My best recommend is to get two or three from junkers. That way you'll have at least one good one for now, and probably another good one to keep on hand for when you need it one day.
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Sven: '89 245 NA, 951 ECU, expanded air dam, forward belly pan reaches oem belly pan, airbox heater upgraded, E-fan, 205/65-15 at 50 psi, IPD sways, no a/c-p/s belt, E-Codes, amber front corner reflectors, aero front face, quad horns, tach, small clock.