I have a colman electric furnace in a late 80's mobile home. When the thermostate turns on the heating elements get hot but the fan will not start for 3 to 5 minutes. It will start after this time and run out the cycle. What keeps the motor from starting in this 3 to 5 minutes? Yes it is turned off till I get it repaired.

Older furnaces used a limit switch to turn the blower on after the furnaces heated up. The switch could be dirty, not making good contact, or just gotten old. Look for it on the heat exchanger. Clean it up and make sure it is in firm contact with a clean area of the heat exchanger. If that doesn't get it switched on a little sooner, replace it.

But the fan does come on, right? It is perfectly normal for the burner to light and heat up the heat exchanger before the fan comes on.