Goodman GMSS960803BN Error Code 2 Flashes: Pressure Switch Stuck Closed
What Does Code 2 Flashes Mean?
Two flashes on the GMSS960803BN's Integrated Control Module indicate the pressure switch circuit is closed when it should be open. Before energizing the inducer, the board runs a pre-start check expecting the pressure switch to be in its normal resting state — open. If the switch already reads closed at that moment, the board refuses to start the ignition sequence, because it can no longer trust the switch to verify safe venting later in the cycle.
Goodman points to two causes: induced-draft-blower pressure-switch contacts that are sticking closed, or a short in the pressure switch circuit. On this single-stage furnace there is one pressure switch doing this job, so a stuck or shorted switch stops the whole startup rather than just changing a firing stage. Contacts that have opened and closed through many seasons can weld slightly or gum up with corrosion and fail to spring back open when the inducer is off.
It helps to keep this code distinct from its opposite, the 3-flash "pressure switch stuck open" condition. Three flashes means the inducer is running but the switch never closes to confirm draft; two flashes means the switch is closed at rest before the inducer runs at all. Both point at the same component and its wiring but describe opposite failures, so the diagnosis differs.
What You'll Notice
- The furnace will not start a heating cycle even though the thermostat is calling for heat
- The inducer motor does not spin up at the start of the sequence
- The diagnostic LED blinks twice, pauses, and repeats
- No burner ignition and no warm air, with the furnace essentially inactive
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Pressure switch contacts sticking closed | Most common | ✗ Call a pro → |
| Short in pressure switch circuit wiring | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms the pressure switch state with the furnace at rest, since the code means it is reading closed when it should be open. They test the switch contacts independently and inspect the switch harness and connector for a short that could complete the circuit regardless of the switch's real position. Because the failure is either a stuck switch or a wiring short — both requiring component testing and replacement — the repair is professional work rather than a homeowner task.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The furnace will not start and the LED shows two flashes
- The inducer motor never runs at the beginning of the cycle
- The pressure switch was replaced but the two-flash code returns
- You suspect a pinched or chafed wire in the pressure switch harness
Frequently Asked Questions
What is the difference between 2 flashes and 3 flashes on my Goodman furnace?
Two flashes means the pressure switch is stuck closed before the inducer starts, so the furnace never begins. Three flashes means the inducer is running but the switch will not close to confirm draft. They involve the same switch but are opposite faults.
Can I just replace the pressure switch myself?
This furnace marks the pressure switch as a professional repair. The switch must be matched to the exact setpoint for this model and the circuit checked for a short first, so a technician should test and replace it.
Why would the pressure switch stick closed?
The contacts open and close every heating cycle for years and can eventually stick from wear, corrosion, or debris, failing to spring back open when the inducer is off. A wiring short can also make the board read the circuit as closed.
✓ Verified against manufacturer service manual — March 2026