I have read the different posting and replys, but they don't seem to address my problem. Friend has an older Kenmore Power Miser 70 that has an old electronic ign. (no flame senser). The furnace will heat when the fan switch is set to "on" position, and it will cycle the heat. When the fan is switched to the "auto" position, the igniter will light a pilot flame, but the fan will not come on and after a few min. the system will shut down. I can hear a click after a short period, then the pilot will go out. Any help would be appreciated.

I don't think there is anybody here that really understand how all these different system work. I do my best. I am sure you saw references to the blower not coming on due to a relay or limit switch. Normally the blower shouldn't come on until after the main burner. If it doesn't come on then, another limit switch shuts the system down. I would try to identify the relay and limit switches and see if they seem to be working. Also clean them.

I would ask about a thermocouple for the pilot light, but if that was the problem, I don't see why it would heat with the fan on. I am afraid I can't help much other than to say poke around and get back with what you find.

Thanks Labman, I will continue to dig and if I find the solution I will post it.