what are these wires for ?

[blazer2007]

I was trying to find out what or where they go or if I even need them.The blazer is a 1978 which originally came with a 6 cyl. with standard tranny.Is now a 454 with no heater and has all mech. gauges.The 4 wires are a large orange wire and 2 smaller blue looking wires and a small brown wire. They couldn,t help on the elec forum so I thought I would try the blazer side since it is a blazer

[blazer2007]

oops ,clicked the wrong button ,here is a pic