My Goodman furnace GMS80903BNA Keeps recycling before reach temp in the house; the 4-blinks indicates an open primary limit switch, verified with the meter. Is it a faulty switch or something else?

On - OK
1 Blink - Ignition failure. Check Gas flow, gas pressure, gas valve, flame sensor.
2 Blinks - Closed pressure switch. Check pressure switch (stuck in closed position).
3 Blinks - Pressure switch - failre to close. Check venter, pressure switch, vent blockage.
4 Blinks - Open limit switch. Main limit or aux limit are open. (My comment - Means overheating in chamber. Often result of blocked intake air. Bad filter. In my case, plastic wrap had been sucked into the intake. )
6 Blinks - False flame sensed. Check sticking gas valve.
Rapid continuous blinking - Incorrect twinning, incorrect primary polarity. Reverse transformer secondary leads, reverse primary wires.

Closed pressure switch can be from dirty combustion vents, bad chamber pressure - like missing screws, maladjusted gas pressure, failing pressure switch, loose hoses, moisture in the hoses or fan blades The switch need to be closed to ge the unit to work

TRI-COLOR (DSI LED) DIAGNOSTIC TABLE
No. of Red BLINKS
1 Flame sensed when no flame should be present
Verify the gas valve is operating and shutting down properly. Flame in burner assemble should extinguish promptly at the end of the cycle. Check orifices and gas pressure.

2 BLINKS Pressure switch stuck closed/ inducer error
Pressure switch stuck closed. Check switch function, verify inducer is turning off.

3 BLINKS 1st-stage pressure switch stuck open/inducer error
Check pressure switch function and tubing. Verify inducer is turning on the pulling sufficient vacuum to engage switch.

4 BLINKS Open limit switch Verify continuity through rollout switch circuit.

5 BLINKS Open rollout/open fuse detect Verify continuity through rollout switch circuit, check fuse.

6 BLINKS 1st-stage pressure switch cycle lockout If the first stage pressure switch cycles 5 times (open, closed) during one call for heat from the thermostat the control will lockout.Check pressure switch for fluttering, inconsistent closure or poor vacuum pressure.
7 BLINKS External lockout (retries exceeded) Failure to sense flame is often caused by carbon deposits on the
flame sensor, a disconnected or shorted flame sensor lead or a
poorly grounded furnace. Carbon deposits can be cleaned with
emery cloth. Verify sensor is not contacting the burner and is locatedin a good position to sense flame. Check sensor lead for shortingand verify furnace is grounded properly.

8 BLINKS External lockout (ignition recycles
exceeded where flame is established and then lost)Check items for exceeded retries listed above and verify valve is not dropping out allowing flame to be established and then lost.

9 BLINKS Grounding or Reversed polarity Verify the control and furnace are properly grounded. Check and reverse polarity (primary) if incorrect.

10 BLINKS Module gas valve contacts energized
with no call for heat Verify valve is not receiving voltage from a short. If a valve wiring is correct and condition persists, replace module.
11 BLINKS Limit switch open - possible blower
failure overheating limit Possible blower failure, restricted air flow through appliance or duct work. Verify continuity through limit switch circuit and correct overheating cause.

12 BLINKS Module Ignitor contact failure Fault code indicates the module ignitor contacts are not functioning
properly. Replace module.Solid Module - internal fault condition Module contacts for gas valve not operating or processor fault.
Reset control. if condition persists replace module.
3 double 2nd-stage Pressure Switch Stuck Open/Inducer Error
Check pressure switch function and tubing. Verify inducer.

That blinking 3 times is indicating a pressure switch problem. Try checking for water or a blockage in any of the hoses going to the pressure switch or condensate drain. Check the air intake and exhaust pipe for any blockage including any saggs that may hold water. Make sure condensate drain or pump is working. If you get a glow from the igniter, there may be a blockage in the gas valve or piping.

This indicates a open limit switch on the furnace, the heat exchanger is getting to hot therefore the limit switch is opening and not allowing the furnace to work properly. Did the techinician check the limit switch on the unit?

4 blinks indicates a failure at the high limit switch. This switch is usually located on the heat exchanger face plate and has two wires going to it. Usually it fails because the furnace has over heated. The most common reasons are a plugged filter or coil that is limiting the airflow over the heat exchanger. Turn off the power to the furnace, replace the filter, clean any coils in the plenum and verify that all the vents in the home are open. Then turn the power back on and see if it is fixed. :)
If the above solution does not fix the problem, the limit switch itself may be bad from excessive heat. Replace it with a new one. Good Luck!

it sounds like the low temp limit switch, the one that cools the furnace down with the burner off and the thermostat open, when it cools to a point the fan stops, the other switch in burner area turns burner off/on, hope this helps

Natural gas furnace??? If so, your flame sensor switch might be bad. Once your burners ignite, they close a limit switch that lets the control module know that the gas ignited- so you don't blow gas into your house uninterrupted. Let me know if you are talking about something else.

sounds like the primary limit typically behind the gas valve its larger then the others, rectangle in shape with 2 wires going to it. be careful if your bypassing limit this can create a very hazardous condition

limit switch is on the heat exchanger black plastic about 1and1/2 in. by 2 in. with 2 wires going to it , it has 2 screws holding it in take it out and check it with an ohm meter and you should not have a reading if it is good