Hello all who are viewing this. I have installed various police cars but, they all share the same problem. Whenever I activate the sirens, the lights do not show up? Can someone please help me resolve this issue? Thank you.

Do you have ELS installed?

Most likely they are ELS (emergency lighting system) cars which use an entirely different system than the normal GTA IV cruisers. You must install ELS for them to work, and by default the lights are turned on manually by pressing j, and the traffic advisor with k, completely separate from the siren.

Yes, I installed it and nothing happened. I tried activating the sirens, only the sound reacted and the lights continued to be off. Can you please tell me how to properly install ELS? I most likely did it wrong.

 

With ELS installed, the Siren and Lights are separated.

 

You toggle your primary (Red Blue, Red Red, Blue Blue) lights with J

You toggle your secondary lights (Amber) with K

 

Then there's also the option to display a configuration menu (ALT+M), where you can change the lightmodes for primary (U) and for secondary (I).

Oh. Thank you for tellin' me. Also, I have another question that is completely not relevant to this specific issue. I am curious, how do you re-texture cars and stuff? I know how to install cars, just not re-texture.

Well you need the template for the car (they're usually provided within the zip or rar). Then you just "paint" over that template and replace the texture inside the .wtd - Sounds difficult but it really isn't. Make sure to check out the tutorial in the tutorials section. (And do me a personal favour, don't upload your first few skins - wait until you get better at it)