As from the factory, the low beam headlights are part of the bulb failure warning system; the high beams are not.

Supposing that your brick has the original headlight wiring, and the BFWS light comes on when you switch to high beams, then something else is going on.

The BFWS light is triggered by an imbalance in the current draw between the left side bulb and the right side bulb for only the low beam headlingts, tail lights, and all three brake lights.

So anything that causes an imbalance sets off the system. Bad ground connections? Different brand of bulb, oxidized contact on a bulb, lots of possibilities. And - the BFWS relay itself has been known to fail.

If your BFWS lights is flickering, there may be a weak contact in a connection. Check the connectors for the headlights, they can fail even though they are weatherproof.

Goog luck,

Bob

:>)
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240s: 1986 244GL, 1988 244GL, and 5 others.