I have a Daewoo GC25P (Old truck) that has no spark. No coil output. The coil has 3 wires. Two are power (12v) with power present, one is negative not present from distributor. Distributor is 4 wire. Wondering what the 4 wires are. Two of them seem to be ground when probed. Other two wires had low voltage when cranking (.3v and.8v). Don't know where they come from. Any ideas? Thanks.