I have a problem with my light too - but in my case the light goes off as soon as the engine starts but comes on as soon as the car moves forward.
I am told this behaviour indicates a sensor fault. If yours never goes out, I would suspect the module rather than a sensor. Could you borrow one from a nearby board member to check. Or depending where you are there is on for sale for a 530 on ebay in the UK currently.
Hope this helps