generic headlight relay

[Cal25]

I bought a replacement headlight assembly and before I get started I would like to get a relay to add to the circut. Thinking of bringing a wire from the battery to supply the relay.

What type of relay do I get? If one off a certain car would work it would be easy to pick up at the auto parts store.
Thanks everyone.

[katoranger]

They have fog light install kits at most auto parts stores. Common relay. They probably have just the relay and socket available too.

One of those should work fine.

[Cal25]

I found a generic relay at the auto parts place. Need to get one more as it only does one circut.

[Weldangrind]

I would use a generic Bosch-type relay, which is easily identified by the odd numbering on the terminals (85, 86, 87, 87a and 30). If the schematic isn't printed on the outside of the relay, a few minutes with a 9 volt battery and a multimeter (set for continuity) will make it clear. Terminals 85 and 86 are the coil wires, and higher-end relays have a diode built in, so look for + or - signs near 85 and 86. Terminal 30 is the common terminal, and it connects with 87a at rest, 87 when energized.

What that means is that you can control two circuits with one relay. If you wanted to make a high / low beam circuit, connect the low beam to 87a and the high beam to 87. Once you apply power to the relay, it will transition from low to high with one switch.

Apologies if you already knew this stuff.