Goodman GMEC960803BN Error Code Red 3 Double Flashes: 2nd-Stage Pressure Switch Stuck Open / Inducer Error

What Does Code Red 3 Double Flashes Mean?

Three red double-flashes on the Goodman GMEC960803BN's Integrated Control Module mean the second-stage (high-fire) pressure switch did not close when the furnace tried to move to high fire. As a two-stage furnace, this model runs the inducer faster for high fire and uses a separate high-fire pressure switch to confirm the increased draft before allowing full firing rate.

When that second-stage switch stays open, the board cannot verify safe high-fire venting. The usual causes are a faulty high-fire pressure switch, blocked or kinked pressure-switch tubing, or an inducer that is not pulling enough vacuum at the high-fire speed. Because the low-fire switch may still be closing normally, the furnace can sometimes run on low fire while failing to reach high fire.

This is the high-fire counterpart to red 3 flashes (first-stage/low-fire switch stuck open). Together with red 2 flashes (switch stuck closed) and red 6 flashes (pressure-switch cycle lockout), it is part of the venting-safety interlock chain. All are high-severity and require a technician.

What You'll Notice

• The furnace heats on low fire but never steps up, and the board shows a red triple double-flash
• The home struggles to reach temperature on very cold days because high fire is unavailable
• The fault appears at the moment the furnace attempts to move to second stage
• The inducer may audibly change speed just before the code appears
• Repeated failure to sustain high-fire operation

Common Causes

How This Is Diagnosed

Because the second-stage switch did not close, a technician verifies the inducer ramps up to its high-fire speed and pulls adequate vacuum, then checks the high-fire pressure-switch tubing for blockage or kinks and tests the switch itself for correct operation. The vent system is also checked for restriction that would only show up at the higher draft demand. This pressure-switch and inducer work is a professional repair.

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 runs on low fire but never reaches high fire
• The code appears specifically when the furnace tries to step up to second stage
• The home cannot keep up during very cold weather
• Any diagnosis involving the high-fire pressure switch, its tubing, or the inducer

✓ Verified against manufacturer service manual — March 2026