Hello, I have a Puch maxi, the problem is that the horn won't work when the lights are on. It will work fine when the lights are off. I have checked all connections and cleaned but still no luck. I am wondering if it could be the light coil, but how would i test it and would it just lose power? Can the light coil be cleaned ? Is it possible to upgrade to a 12v coil? Any Help would be fantastic thanks.