Using a relay to activate and deactivate multiple switches

Thread Starter


Joined Nov 14, 2019
Need some advice and help please.

I have a set of aftermarket car tail lights that come as 4 units because you have the outside and the inside on each corner. On each of these light units there is a 2 wire switch that turns a sweeping sequential light on or off. So I am assuming if the switch is on it basically makes the contacts of those two wires connect and if it's off it makes the contact not connect.

What I want to do is dynamically change that based on a relay NC or NO. So if I was to put one end of that wire through the common and the other end on NC or NO then that works. However, problem is I have to put 4 different relays to do the same thing 4 times on 4 of those light units. All 4 relays will all need to be energised with the same power source so it seems kind of a waste.

Is there is neater way to do it his where I can use a single relay ?


Joined Jun 8, 2013
So each light unit has multiple lights that sequentially light from a bulb at one end of the unit to the other end?

What is the lighting effect you are trying to achieve?