As above - just test them with a 9v battery - the one that will be the switching wire that comes from the stalk will be the one that clicks. There is usually a small diagram on the relay as well. The feed will be permanent live from the battery. Check this page out - 86 is switched, 87 to headlights, 30 from battery (+, fused) and 85 to battery (-)
https://www.danielsternlighting.com/tech/relays/relays.html