Ignition light needs high revs to go out

[Gracol2001]

I have a transit mk3 transit 2000cc(pinto) when the van is started the ignition light stays on unless I give it high revs. Once out it stays out, but if not given high revs will stay on till van reaches about 30mph.Charging checks out ok. Even when light is on. Any suggestions what to check?

[dumper]

Are you sure the belts not slipping what do you call high revs my mk3 after fitting a slit charge relay I had to flick the throttle to put the ligh out .it’s probably the alternator at fault but to test if it’s a wiring problem you could make up a lead straight to the battery for the main lead and get a lead with a bulb holder in it for the warning light put that straight to the battery and start it up see if it does the same if not then you have a wiring problem.

[Gracol2001]

Thanks for the help. Checked the belt no problem there. The alternator was renewed at the start of the year, thought this might have been then issue, your bit about the split charger, I disconnected mine and problem disappeared. Will replace split charger to see if it helps. The light goes out at 2400 revs.
Thanks for the tip.

[dumper]

I had two different split charges on mine both did the same but it didn’t need many revs to do it and they were the type that used the warning light feed to trigger the relay .