Blimey Rob this one just won’t lie down! From what you say you have done now all sounds good to me. Out of curiosity it would be interesting to know if it’s the relay coil or the circuitry in the switchback bulbs that is generating a spike. One little test would be to temporarily disconnect either 87 or 30 from the relay (disconnect the DRL's). If it still jumps then the relay is still suspect but if it doesn’t then the circuitry in the switchback bulbs may be somehow causing it.
