I have an old furnace - I would say about 25-30 years old. The blower was broken - we had that fixed. We suspected the thermocoupler was bad - we had that fixed. Now when we turn it on all work except the blower runs for a couple of seconds and goes off. Could the problem be the limit switch, or something else? Thank you!

When your furnace gets that old, then you can expect parts to go seriously wrong and you wind up with no heat. Then you start spending money to repair almost every winter. I got sick of that and just bit the bullet and got a new hi energy efficient furnace for $5000. Now I don't worry when it gets cold. I know everything is going to work properly.

Sorry, I couldn't answer your question, but I just got fed up with furnace problems and spending money on repairs and parts.

Tick

Sounds like you need your fan limit adjusted or replaced.