tazdevil

i have a merc 496 mag transom harness 865677a01 i have identified steering sensor,digital trim, analog trim,pitot,mercathode, and there is a long harness with 3 wires with bullet connectors which is unidentified purple green and blue can someone help me please

BUP

I take it you have a 496 with DTS

Blue is trim up to pump
Green is trim down to pump
purple is trim relay power

If I remember correctly but not 100 % about this for these 3 wires is do not plug these wires in all at the sametime with your battery hooked up / power on. Anytime working with wiring and plugs in unhook battery power / or battery turned off especially on computer controlled marine engines..

tazdevil

yes it 496 mag dts

BUP

I really already knew you had DTS by the way you were describing your transom wiring. Anyways your blue, green and purple wires are listed in the post above. Good luck