Morris Minor Owners Club

When the main lights are on the ignition light stays on when engine is reving then goes dim, when the engine returns to tickover the ignition light goes out, works ok during the day (or I don't notice), any ideas??

Thanks, John

It's not getting enough charge to handle the extra load of teh lights (and you might not be getting a great deal more than the bare minimum with them off too).

Could be:

Dynamo
Regulator
Wiring (battery cables/ earth, regulator wiring/ terminals, dynamo wiring/ terminals)

If you've got an alternator then ignore the above other than battery and alternator wiring/ terminals (including solenoid!) and look to needing a new alternator asap. Also if you've got an alternator, there's a hell of a lot will fit from the xcrappies - Various Fords, BL stuff, Rovers etc had ones with the right socket on teh back and handed brackety parts. A good one if you can find it is the Montego turbo diesel (might be the same as the NA diesel) as it puts out a fair few amps

Check the (easily removable and replaceable) brushes on the dynamo. On my first Minor they were nearly worn out and in the dark you could see sparks inside the dynamo when the engine was running.