I have a mobile with a forced air Coleman electric heat. The fan will not run in the auto setting (switch by motor in cabinet) but the element will heat up. In manual the fan runs constantly and heat comes on with the thermostat. The heating company recently replaced the sequencers and said we shouldn't have any more problems, as they also replaced the block that mounts everything $500 aprox. Where can I find testing info on the heater or troubleshooting info? I have electronics experience, but none with these.

Sounds like a bad sequencer again. The sequencer is time-delay activated from 24 volts from t-stat. Blower comes on first then each bank of strips are timed on. You can only test it with the power on calling for heat. Very dangerous if you do not know what you are doing. You have a 115volts on the strips,blower and sequencer at all times. When the sequencer closes it gives 230 volts to the parts to make them work. I repeat very dangerous if you do not know what you are doing.

Furnace will not shut off when turned down