My heater could be started automaticlly but the fan could not. I have to switch it from Auto to On. I found 5 wires on the to the relay from blower. I have seen the fan will be automactilly started without A/C during summer, but A/C and fan could be worked at same time with no issue. Do you know what is simpler and cheaper to fix by myself. Thanks

The heater should have a fan and limit control somewhere on the unit. The fan control is used on the heat side when the furnace turns on for heat. It automatically bring on the fan. Sounds like the fan and limit control is defective.

Do you think it is relay's issue for this problem, how I can fix by myself to save money? Thanks

Start with Brand of heating unit?
Exact model of heating unit?
Relay brand you have ?
Exact relay part number?

First of all, thanks for your quickly respond.

Do you mean that I need to provide these info you asked, then you will find some one can fix my problem/

do you mean that I need to provide these info you asked, then you will find some one can fix my problem/

Usually if I cannot figure it out or some other folks that help on the board cannot figure it out you will be calling for ON Site service at your home.

I do not run around the country looking for people to fix furnaces for folks who post there problems here. I cannot afford the plane fare.

Nice. I will call On site service in my area for fixing my problem. Thanks again

I was trying to help you but I need the info first. Then I can look up your furnace. Sorry but I cannot fix it by remote control with out info.