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Error code reference

Goodman Hvac Error Code 3

End switch is closed without inducer motor running, indicating a stuck or failed end switch.

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End switch is closed without inducer motor running, indicating a stuck or failed end switch.

First step from the service manual

Check end switch on inducer motor.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 3 means on a Goodman hvac

Goodman fault code 3 indicates that the inducer end switch (also called the pressure switch or draft inducer pressure switch) is detected as closed while the inducer motor is not running. Under normal operation, the end switch should only close after the inducer motor starts and creates sufficient negative pressure in the flue system. When the control board detects this switch in a closed state during a period when the inducer is off, it flags the condition as a fault and locks out ignition to prevent unsafe operation.

This fault most commonly points to a mechanically stuck or failed end switch that is holding itself in the closed position regardless of actual pressure conditions. The switch may have failed due to age, corrosion of the diaphragm, or debris in the pressure sensing port or tubing. Less commonly, the issue can be traced to a short or wiring fault in the circuit between the switch and the control board, which causes the board to read the switch as closed even when it is physically open. A collapsed or pinched pressure sensing hose can also trap pressure and keep the switch closed after the inducer shuts down.

Diagnosis should begin at the end switch itself, located on or near the inducer motor housing. With the unit powered down, disconnect the pressure sensing hose and inspect it for blockages, cracks, or kinks. Use a multimeter to check continuity across the switch terminals: the switch should be open (no continuity) when the inducer is not running. If continuity is present at rest, the switch has failed in the closed position and requires replacement. Also inspect the wiring harness for pinched insulation or shorted conductors.

Source: manufacturer service documentation.

Common causes of 3

  1. 01

    Failed or stuck end switch

    Part replacement

    The end switch diaphragm has failed mechanically, holding the contacts closed regardless of whether the inducer motor is running. Confirm by checking continuity across the switch terminals with the inducer off: a reading of continuity indicates the switch has failed closed.

  2. 02

    Shorted or damaged wiring in switch circuit

    Wiring / connection

    A short circuit in the wiring between the end switch and the control board can cause the board to read a closed switch signal at all times. Inspect the wiring harness for pinched insulation, bare conductors, or connectors that have been pushed together.

  3. 03

    Blocked or collapsed pressure sensing hose

    Wiring / connection

    If the small rubber hose connecting the end switch to the inducer housing is kinked, collapsed, or clogged with condensate or debris, it may trap residual pressure that keeps the switch closed after the inducer stops. Inspect the hose for physical damage or blockage.

  4. 04

    Water or condensate contamination in the switch

    Part replacement

    Condensate can migrate up the sensing hose and into the switch body, causing the diaphragm to stick in the closed position. This is more common in high-efficiency furnaces that produce significant condensate.

  5. 05

    Faulty control board

    Part replacement

    In rare cases, the furnace control board may incorrectly interpret the switch circuit state due to a failed input circuit on the board. This is typically the last component to suspect after the switch, wiring, and hose have all been ruled out.

See the test procedure for each cause

Frequently asked questions about 3

What does 3 mean on a Goodman hvac?
Fault code 3 on a Goodman furnace means the inducer end switch is detected as closed while the inducer motor is not running. This indicates the switch is stuck closed or has failed. The furnace will not attempt ignition while this fault is active. The end switch and its associated wiring and pressure hose should be inspected first.
Can I fix Goodman fault code 3 myself?
Inspecting the pressure sensing hose for kinks or blockages is a task many homeowners and DIYers can perform safely with the unit powered down. However, testing the end switch with a multimeter and replacing it requires some familiarity with electrical components and furnace disassembly. If you are not comfortable working with HVAC electrical components, a qualified technician should handle the repair.
Is Goodman fault code 3 a safety hazard?
The furnace control board prevents ignition when fault code 3 is active, so there is no immediate combustion risk while the lockout is in place. However, the underlying fault means a critical pressure safety switch is not functioning correctly. The system should not be bypassed or forced into operation until the root cause is identified and corrected.
How much does it cost to repair Goodman fault code 3?
If only the pressure sensing hose needs clearing or repositioning, costs are minimal and may only involve a service call fee, typically in the range of $75 to $150. Replacing the end switch itself usually brings parts and labor costs to somewhere between $150 and $350 depending on the specific model and local labor rates. A faulty control board, if that is the root cause, can increase costs significantly, often ranging from $300 to $600 or more.
Will resetting my Goodman furnace clear fault code 3?
A power reset may temporarily clear the fault code display, but if the end switch remains stuck closed, the fault will return immediately when the control board runs its startup checks. A reset does not fix the underlying mechanical or electrical problem. Permanent resolution requires diagnosing and repairing the failed component causing the switch to read closed without the inducer running.

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