Obviously, this is the most popular question in this forum. It is also easily answered and minor variations of the same question will not produce a different answer.
So, to prevent having to type the same thing time after time, here goes:
All lights on vehicles in BC are controlled by
Division 4 of the Motor Vehicle Act Regulations
The first thing you want to concern yourself with is
Division 4.02(2) MVAR
Is it functionally equivalent to the original? Do the DOT/SAE/E code letters on the lens assembly match EXACTLY with what you are replacing, and are all lens colours EXACTLY the same?
If not, then the answer is NO, you can't do it.
This particular section also talks about lenses, bulbs and reflectors being marked in accordance with the Motor Vehicle Safety Standards. If there are no DOT/SAE/E code markings then NO, you can't use them.
If you are adding extras instead of changing what is already there, you have to satisfy BOTH what has already been explained above AND is it authorized by Division 4.
If you cannot answer yes to BOTH conditions in the last paragraph, then it is illegal.
For colour, the average vehicle is allowed red, yellow and white, and then only in the proper places. ANY OTHER COLOUR is illegal unless supported by a permit issued by ICBC or specifically mentioned in Division 4. Unless you are a police vehicle, you cannot have blue lights.
The General Maintenance Rules require that the lights be securely mounted, not broken, kept clean and properly sealed against water and not be covered or shielded or obstructed by ANYTHING.
If you put anything in, on or over a lamp or reflector that reduces its effectiveness IN ANY WAY, it is illegal.
Flashing lights that are not signal lights or hazard flashers are illegal unless you are specified in this part of Division 4.
I have a page from Transport Canada about headlights. If you are interested, PM me and I will get it to you.
All lights not specifically authorized for use are
Off Road Lights and must be covered with an opaque cover when the vehicle is being driven or parked on any highway.
"highway" includes
(a) every highway within the meaning of the Highway Act,
(b) every road, street, lane or right of way designed or intended for or used by the general public for the passage of vehicles, and
(c) every private place or passageway to which the public, for the purpose of the parking or servicing of vehicles, has access or is invited;