I changed some 2d lights for less but only 2 are working properly. The other two only come on after about 1 minute but one light is dim and only a few volts showing. I switch the 2way switch and the dim one now becomes full brightness and the one the was at full brightness now becomes dim. I'm thinking possible revered polarityor I'm switching a neutral
A guess again have you fitted LED replacements into a fitting with an electronic ballast? The LED units will only work with magnetic ballast units.
Could be one of a few things? Is there a dimmer involved? If so, are the led bulbs you brought dimmable?. Is there a chance things have some how got wired in series instead of parallel.