FieldBench

Goodman

GSX16

AC · Single-stage outdoor AC · contactor + dual cap

Goodman single-stage condensing unit. Contactor, dual run capacitor, piston or TXV indoor. No ComfortBridge outdoor board, no GSXC18 two-stage comms. Faults are mechanical: cap, contactor, fan, charge — not furnace E-codes.

Not GSXC18 (two-stage / communicating outdoor). Not GSZ14 / GSZB (heat pump — reversing valve + defrost). Not GLXS4B / GLXS4M (R-32 single-stage). Not a furnace IFC.

Walk this in Diagnose

This plate

Stages
Single-stage scroll · contactor
Metering
Piston or indoor TXV depending on coil
Pair
24V Y from any conventional furnace / AHU

This board

Contactor + fan — no communicating outdoor PCB

  • There is no 7-seg on this outdoor. If someone is reading E2, they are on the indoor furnace.
  • HPS / LPS (when equipped) open the contactor coil. Reset / auto depending on vintage.
  • GSX14 is the 14-SEER sibling — same contactor story, different rating.

Sequence

  1. Y. 24 VAC at the contactor coil → compressor and outdoor fan. Indoor blower on the cool tap / G.

Faults on this IFC

  • No Y

    Outdoor silent

    warn

    No 24 VAC at the contactor or the coil is open.

    • Y and C at the outdoor. Indoor IFC / stat actually closing Y.
    • Contactor coil ohms. Do not confuse a furnace lockout with a dead outdoor.
  • Hum / no start

    Cap / start

    lockout

    Compressor hums, outdoor fan may run.

    • Dual cap (fan and herm). Replace on values, not just a bulge.
    • Hard-start only after the cap and windings are proven.
  • HPS

    High pressure

    lockout

    Outdoor airflow, overcharge, or restriction.

    • Fan running? Coil dirty? SC vs nameplate on a TXV coil.
  • LPS / freeze

    Low pressure

    lockout

    Charge, indoor airflow, metering.

    • Do not add gas on a frozen coil. Indoor filter/coil first.

Workflows

No cool, GSX16, furnace is GR9T96 / GR9S96 / GMSS96

Indoor running, outdoor dead.

  1. This pair is 24V Y. There is no ComfortBridge outdoor to talk to.
  2. 24 VAC across the contactor coil. Then cap, then pressures.
  3. Charge: piston = SH. TXV indoor = SC. Do not mix those.
  4. If the indoor is GMVC96 on data wire, this outdoor still wants Y — data wire into a GSX16 does nothing.

Test points

Charge
Nameplate + line-set. SH on piston, SC on TXV.
Cap
Dual can. Fan and herm both in spec.

Gotchas

  • GSXC18 is the two-stage / comm outdoor. Wrong board, wrong charge story.
  • GSZ14 is the heat-pump sibling — add the RV and defrost board before you treat it like this AC.

Related plates

  • goodman-glxs4b — Current R-32 single-stage. Same contactor, wrong refrigerant.
  • amana-asx16 — Amana-badge 410A single-stage. Own chart.
  • goodman-gsxc18 — Two-stage / communicating outdoor. Not this contactor unit.
  • goodman-gsz14 — Single-stage heat pump. Same contactor idea plus RV / defrost.
  • goodman-gr9s96 — Common 24V indoor pair — furnace EE-codes are not this outdoor.