carrier 58TUA won't shut off

Yep, error code 12 Replace control board after replacing thermostat. Workey long time. Bubba

It is the cycle that the heater goes through when the power is returned AND the wall thermostat is calling for heat. [90 sec. blower run time.]

If the blower won't quit running after you plugged in the heater, and you are sure the wall thermostat [fan] switch setting is to AUTO, then it is likely you have a situation that requires a qualified CARRIER service tech see why it's doing what it's doing. I know what the problem is, and it [honestly] should be checked out. You [might] have either a firebox failure, flame roll out condition, or a conditioned air mixing with combustion air problem. All of these are dangerous and should not be addressed by a DIY. Call a licensed HVAC company and have them check your unit.

Maybe I stated the problem wrong I have thermostat turned off yet furnace starts to run heats the house It just never stops LED does go red after 90 sec another thing that troubles me is that if board is bad can I trust the error code that I'm reading from the board?

Sounds like you need to call a repair company.

Or, if you like, you can replace parts till you get the right one.

Nope. Never trust the error code. Get a new board. You might need a new gas valve and igniter too. After that, replace the thermostat and match it with braided thermally shielded blue conductor thermostat wiring type FE-8. Bubba

I got it fixed the thermostat cable got shorted in the wall I end up running new one took me all day to get the cable in place thanks

Bubba, he's playing your song. Replace the thermostat (cable).

There's a little difference between replacing thermostat and replacing cable that leads to is. Is it not Stormin Mormon?