No I believe they should work as long as ignition switch is in on position.
Thats the way mine work and its a 77. Sounds like dogey switch or fuses.
Andrew
If the 260 uses a similar switch to the 240 then it's likely to be the switch. I had to dismantle mine last week and clean/file the contacts before my MoT. You will have to bend the tabs back and take it apart - be careful of the springs.
Sort of sorted it
One of the fused links under the bonnet must have had a poor connection
Either that or ind swictch has a poor contact as the high/low now works but low beam still seems dim
Sorted both probs.
Fused link was dicky stopping the lamps from working plus I had the headlight "plugs" wired wrong (prev modified in a former life)
Lights now bright and work again. result !