I have a Carrier 8000TS with WeatherMaker furnace. It puts out enough heat and keeps up with thermostat control however while it is blowing heat there is a very loud clicking sound coming from inside the furnace. It sounds like someone is putting a stick in a rotating fan so I opened up the access doors to ensure a fan wasn't hitting it but the sound continues... any suggestions would help, even a link to some schematics to narrow down the source.

Is the sound coming from the fan? Is something stucK in the blower like a paper diagram that got sucked off the door when the glue went bad?

There is nothing stuck in the small visible fan. When I took a look while it was running the small fan in front seemed to be fine then I heard the sound coming from behind it yet...

Beats me unless the fan blade in the smaller blower/inducer fan lost one of its fan blades.