Did you replace the main headlight relay on driver's kick panel?
Or the high/low relay that's just rear of the battery, on fender wall?

Symptoms sound like bad main headlight relay on kick panel.
If that's what you already replaced, then I'm with Jorrell in suspecting the headlight switch.

As for the high/low relay, it only handles the power delivered to the headlights themselves. So it's failure would not cause the front and rear small corner lights to fail.
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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.