Old Frigidaire FAZ12HS2A window ac/heat unit starts blowing heat gently and then blows cold for awhile then heat again

[Dbama1]

I have a Frigidaire window ac/heat unit that stopped blowing heat altogether one morning. After further inspection I found the heat relay on the control board had completely blown.

I replaced the board with a new one and checked for continuity across the heat element and it checked out. Now the heat will come on low setting for a minute or two and then blow cool then back to blowing heat gently in a cycle. Where should I look next? Thanks in advance.

[Dbama1]

Could the capacitor cause it not "Kick in" to high gear? 

[Nathaniel Peterson]

I would check the wiring and heater TCO. Make sure the connections are good. Not sure on that brand but usually a no heat situation is wiring getting hot from being used and either blowing the TCO or heater.