I have tried to install the ELS, new lighting mod but can't seem to get it to work in game now.  In fact any police car I drive, either stock in game, or mod now the lights don't work, they don't turn on or I just don't know how to bring up the lighting system.  I have read the readme but I only see "combination button" scenarios and don't exactly know what this means. 

 

Could someone explain to me how this ELS mod works and why I can't turn the police lights on anymore?

The default button is J I think, so if that doesn't work, check the ELS.ini if every vehicle is turned "on". So scroll down until the vehicle names come up (like "ambulance" or "police") and there should be "status=". If status=off this vehicle isn't enabled to work with ELS, so just write "status=on" there and check if you can turn on the lights ingame ;)

It may be that you have your Simple Native Trainer keys on (assuming you have that) if that is the case go to Options>Enable/Disbale keys then press 6 to go to the next menu and make sure to save the settings so you don't have to do that every time