How do you fix Goodman EA?

This is electrical work on the furnace supply and belongs to a licensed electrician or heating technician. Reversed polarity is not something to correct by trial and error. If the furnace was just installed or reconnected, call whoever did the work — this is a wiring error, not a fault that developed. Full steps and safety notes are on this page.

Goodman furnace EA: Reversed 115 volt polarity

EA means the incoming line voltage has line and neutral the wrong way round. The furnace refuses to run because reversed polarity breaks the circuit it uses to detect flame.

Applies to: Goodman GMVC96, GMVM97, GCVC96, GCVM97 and Amana AMVC96, AMVM97 series gas furnaces with a two-character alphanumeric display.

What it means

Flame detection depends on rectification, which passes a very small current through the flame to ground. That only works if the electrical supply is connected correctly and the furnace is properly grounded, so the control checks polarity before it will do anything else. When the check fails it displays EA and stops. This is not a component failure — it is a wiring error, and it is almost always either a new installation that was never correct or the immediate consequence of recent electrical work. A furnace that ran for years and suddenly shows EA usually means something in its supply circuit has been changed or has come loose.

Most common causes

Line and neutral reversed at the furnace, at a junction box, or at the outlet feeding it.
A recently replaced outlet or newly run circuit wired incorrectly.
A loose neutral connection anywhere in the circuit.
A furnace that has been moved, replaced, or reconnected.
A missing or disconnected ground, which the control may report through the same check.
A control board that has failed in a way that misreads the supply.

How to diagnose it

Establish whether any electrical work has been done recently — in the house generally, not only at the furnace. This fault follows wiring changes far more often than it appears on its own.
If the furnace is newly installed or newly reconnected, treat this as an installation fault rather than a developed failure.
Note whether other faults have appeared alongside it. Reversed polarity and poor grounding also produce weak flame signal and igniter codes, so a cluster usually has one cause.
Do not test the supply yourself unless you are qualified to work at a live panel.

How to fix it

This is electrical work on the furnace supply and belongs to a licensed electrician or heating technician. Reversed polarity is not something to correct by trial and error.
If the furnace was just installed or reconnected, call whoever did the work — this is a wiring error, not a fault that developed.
Have the ground path checked as well as the polarity, since a missing ground causes several other faults.
Do not attempt to bypass the check. The control is refusing to run because it cannot trust its own flame detection, which is the one thing that must be reliable.

Notes

Because the same electrical conditions also produce weak flame signals and igniter faults, a furnace showing EA alongside a history of intermittent codes usually has a single supply problem behind all of them.

All codes for this manufacturer

Goodman and Amana furnace fault codes — every code, with what differs between models.

Models this code appears on

From the manufacturer's per-model database. If your model is not listed, this code may not exist on your board, or it may mean something different — check the model page.

The same fault on other control families

Reversed line polarity is one of the most standardised codes in heating, because the physics of flame rectification give every control the same stake in it: Allied's one flash, Carrier's rapid flashing, Lennox E111, and Trane E61 all name line voltage polarity reversed, matching EA exactly. The site's grounding and polarity hub collects the whole sixteen-code family and explains the mechanism they share — flame sensing needs the neutral where the control expects it.

What the fix costs

EA's fix is two conductors swapped back — the cost is finding where. At the furnace's own connection or a nearby junction box it is short work inside a $75–150 diagnostic (repair cost guide); at an outlet or upstream in the circuit it becomes an electrician's correction, still labour rather than parts. Two accountability notes worth money: a furnace showing EA from its first day was miswired at installation, and the correction belongs on the installer's account; and no version of this fault is fixed by a new control board, so treat any $400–900 board quote against a polarity code as a wrong answer to a wiring question.

DIY or call a pro?

Professional, even though the fault is 'just two wires' — the wires in question carry line voltage, and establishing where the reversal entered the circuit means testing live connections. This is also a code where the right professional may be an electrician rather than a heating company, particularly if the furnace plugs into or is fed from recently worked-on house wiring. The homeowner's role is the timeline: EA after an outlet replacement, panel work, or a handyman visit is practically a confession. And leave the control's refusal in place — it is declining to run flame detection on a supply that would blind it, which is the correct decision made on your behalf.

What this looks like

From the outside, this usually shows up as the burner lights and then drops out a few seconds later — that walkthrough covers what to check in order, and when it stops being a homeowner job.

Sources

Goodman Manufacturing — Diagnostic Code Identification System (model-specific fault code lookup)

This site is a reference, not a substitute for a licensed HVAC technician. Gas appliances can leak carbon monoxide and cause fire. Anything involving gas lines, the heat exchanger, or the flame sensing circuit should be handled by a licensed professional. Pages are written with AI assistance from the sources listed on each page and checked against them before publishing.