Carrier 9200 Code 31 Inducer No Start

[xwing1]

Problem: Inducer Motor Won't Start, Code 31
Carrier Weathermaker 9200 gas furnace that won't run.

It gives Code 31.
Turn off power, turn back on and here is what happens:
1) Normal 90second blower motor runs, normal Code 12 during this.
2) Inducer Motor sometimes rotates like 2 turns like it got a split second of power, then it doesn't come on; sometimes it doesn't rotate at ALL.
3) Code 31 flashes.

I have checked vent piping; cleaned out and flushed water condensate trap and lines.
Sometimes it will work, sometimes it won't. Since it throws the 31 code even if the inducer hasn't run at ALL I know it isn't truly a blocked vent or the condensate trap...without inducer running it couldn't even test those pressures.
Sometimes, I can hear the inducer motor on, shut off a second, back on, illogical like relay or board giving stupid instructions...but randomly it works to make heat sometimes.

I suspect a bad relay and/or computer board...that simply isn't telling the inducer motor to run/at the right times.
ANY HELP!?!? It's getting COLD in Wisconsin now!!
Can I buy the computer board and install it myself? From where? I am handy with tools, soldering etc.

THANK YOU in advance!

[ecman51`]

Inducer motor has to run the very first thing before anything else with the furnace can proceed.If that starts to move and quits, you need to trace wires from it back and test its source for 120 volts. If that is too hard to do, and you are handy with electric, you could snip the hot wire and neutral wire that run that inducer and test the wires leading back toward the controls for 120 volts when you run the furnace, and keep meter on it for about 90 seconds, to be sure that the relay has engaged.

And then you can also either hot wire the inducer to another 120 volt source, or ohms test the motor, if you are electrically handy. There could be a capacitor issue, possibly.

Before you attempt any of this though - THE very first thing I'd do is see if there is a way to try to spin the inducer motor shaft to see if it is bound up, when the furnace is turned off.

[xwing1]

The motor runs just fine, and spins over very easily by hand (you can see it facing you with its plastic end cap/fan with direction arrow showing rotational direction); it's not a motor problem. It simply isn't getting voltage from the computer board when it should be, it seems.

[ecman51`]

What does your unit say code 31 is?

On most furnaces where there is at least power to it, and the inducer motor itself tests good, but there is no power to it, one would suspect the sequencer. That may be a separate item, or be on the contol board. If on the board, a person may have to replace the board.

Be sure to make sure that all connections leading to the control board or module, and what is on them, are all tight. You actually should slide back every connection and reinsert to create a fresh new contact. If any connector feels loose you will need to fix that by crimping connector some before reinserting. This would not be an illogical conclusion since your motor has actually tried to spin some, but just quits.