Furnace Problem...HELP!

My furnace (believe it's a Rheem. Not in front of it so I cant recall exactly) is really acting strange. When the thermostat calls for heat, it will show that the system is running, but ABSOLUTELY NOTHING happens at the furnace. When I go to look in the furnace at the blinking lights, it tells me that the problem is at the pressure control switch. I've been getting by this problem by wiggling the two wires that run to the pressure control switch. Once I wiggle the wires, the furnace begins it tests, fires up the burners and runs fine. It will do this for a few cycles and then eventually, the thermostat will call for heat after the furnace has been off and then, all over again, nothing happens. Sometimes the furnace will run all day or days with no problems and then other times it will only run for few cycles. The last few nights, I've had to get up in the middle of the night and do the "wire wiggle" because I woke up to a freezing house!!
I've read that maybe there could be blockage in the flue, but wouldn't the furnace at least begin running to test for this and turn off after a few seconds once it determines the flue path is not clear? It seems that if the process begins with the pressure control switch testing for proper pressure and making sure the flue is clear, the furnace would at least start up. The problem is that NOTHING happens when the thermostat calls for heat. It's as if the furnace is off. As I stated, once I wiggle the wires to the pressure control switch, the furnace fires up and runs fine.
Maybe I've answered my own question: replace the pressure control switch. Has any ever had this problem? Can anyone with experience give me an idea what's wrong? Please give me your thoughts.
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This is Turtle.
Sure sounds like a fan switch to me.
here is possiblitys to look at :
New fan switch for the diafram is sticking. Water or carbon in the tube coming to it. You need to hire a wire wigglier to wiggle it for you at nite. Call a Service company to check it out and maybe change the Fan Prover Switch / Fan Switch.
TURTLE
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My suggestion: Call a pro.
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Hey, sounds like he needs the autowhacker?
How about pull the wire off (assuming it has a press on plug) adn then sand the terminals, and lightly grease them. Noalox is better yet.
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Christopher A. Young
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alt-hvac Moderated posted for all of us....

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Tekkie

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Let me ask you one question...
WHY in hell are you playing with a unit that could....thats could...kill you since its telling you something MIGHT be wrong?

My thoughts are as always. You have proven you dont know what you are doing. You didnt even know what kind of furnace you have. If you dont know, neither do we. Call someone that can properly diagnose it, and even if it turns out to be very simple, you will have the piece of mind knowing its been looked at by someone that has some idea what is wrong....and not some wild assed guess.
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