Where ia my centrigugal switch on my coleman furnace?

Depends on how old the furnace is. It is either built into the draft inducer motor assembly, or will be located near the draft inducer with a rubber hose between the draft inducer and the switch. If you can post a pic or two of the inside of your furnace, I should be able to tell you what's what.

If it is truly a centrifical switch, it is built into the combustion motor.

If this is the furnace I think it is, there are 4 wires (instead of the normal 2) attached to the motor. The switch wires would be those toward the back of the motor & If I remember correctly, they are blue.

You got it Grady. The ones Ive seen were always blue. And correct that it will be built in if truly a centrifical, vs a pressure switch wich would have course have the rubber tube to it. I liked when they finally wised up and switched over to the pressure switches personally.

I agree. Pressure switches are far preferable, in my opinion, to centrificals. Some Coleman mobile home furnaces have a combustion air damper which must open before the burner will attempt to fire. There is an end switch on those as well.