Coleman Pilot light will not light.
Coleman 7900 series, would it be the thermocouple, if so what is the replacement procedure?

I am thinking there is a simple answer to your problem

Common HVAC Problems, My Pilot Light goes out, Pilot light won't stay lit, The Hannabery HVAC Troubleshooter (http://www.hannabery.com/faq19.shtml)

Think you need to push down on control knob or a button while lighting pilot