light switch poles
 

unfortunetly previous owners/mechanics have messed with the ligt switch...(1980 300 sd) i have wiring schematics & i believe previous owners/mechanics have switched poles on the switch....where can i find which wire/wires goes to which pole? which poles does what? i don't want to have to take switch apart to figure it out and have to buy a new switch. any assistance here would be greatly appreciated!!