FieldBench
Models
Goodmanac

GLXS4B

R-32 single-stage · contactor + dual cap

Current Goodman R-32 single-stage condensing unit (GLXS4B / GLXS4M / GLXS5B / GLXS3B). Contactor + dual cap, same physics as GSX16 — different refrigerant. A2L. Charge and recovery are R-32, not a 410A GSX16 top-off.

Not GSX16 / GSX14 (R-410A). Not GLXT7C (R-32 two-stage). Not GXV9S inverter. Not GSZC / GSZ heat pump.

Diagnose this modelInstall notesBoard cross-refField wiring

Refrigerant

R-32 (A2L). Recover / weigh on an R-32 machine. Do not mix 410A.

Stages

Single-stage scroll · one contactor

Metering

Indoor TXV / piston per the R-32 coil match — not a leftover 410A piston

Pair

24V Y from any conventional furnace / AHU

Sister SKU

GLXS4M multi-family 1.5–3 t · GLXS5B 16.5 · GLXS3B 15 · Amana ALXS4B

This board

Contactor + fan — R-32 nameplate, no communicating outdoor PCB

  • No 7-seg on this outdoor. Indoor E2 is the furnace.
  • HPS / LPS (when equipped) open the contactor coil.
  • Rating plate says R-32. A 410A gauge set and a GSX16 charge chart are the wrong book.

Nothing to recall. Watch the contactor and the R-32 pressures.

Universal swap

No universal

Goodman GLXS4B outdoor. No furnace IFC universal. Replace the OEM outdoor control / contactor / drive by the silk.

Silk: GLXS4B

White-Rodgers

—

ICM

—

Honeywell

—
  • Indoor furnace universals (50A55, 50M56U, ICM282B, ICM2811, S9200U). This is not an IFC.
  • Do not ‘adapt’ a furnace board to an outdoor inverter, defrost PCB, or contactor.

After you pull the dead card

  1. 1Photograph the outdoor silk. Indoor 50A55 / ICM282B / S9200U do not belong here.
  2. 2Contactor units: replace the contactor / cap / HPS — there is no universal outdoor board.
  3. 3Inverter / communicating outdoors: OEM drive only. There is no White-Rodgers or ICM outdoor universal.

Field wiring

Written landings for Goodman GLXS4B. Not a factory schematic.

Single-stage 24V contactor
Conventional Y / CR-32 · A2L

One cool stage. Indoor transformer, stat Y, outdoor contactor coil. Dual cap on the outdoor. No data pair and no Y2.

Written circuit description only — FieldBench does not redraw maker schematics. Example: R to W closes on a heat call; verify 24V at W1 before you change the IFC.

Open manufacturer PDF

This indoor

24V Y. Same screws as GSX16 — R-32 nameplate.

24V single-stage

Plate is a one-contactor condensing unit.

Wall thermostat

Conventional 24V. One cool stage.

  • R24V hot from indoor transformer24V
  • C24V common24V
  • YCool call — one stage24V
  • GIndoor fan24V
  • WHeat. Stays at the indoor.24V

Indoor IFC / AHU

Y in from the stat. Y out to the outdoor contactor. Same transformer.

  • RTransformer hot — feeds the stat24V
  • CTransformer common — must reach the outdoor24V
  • YStat Y in24V
  • YoutTo outdoor contactor coil24V
  • GBlower / cool tap24V
  • WHeat only24V

Outdoor — contactor coil

Two control screws. There is no outdoor IFC to interrogate.

  • YContactor coil. ~24 VAC to C under a call.24V
  • CContactor coil common24V

Outdoor line

208/230 through the disconnect to the contactor line side.

  • L1LineLine
  • L2LineLine
  • GNDEquipment groundLine

Dual run capacitor

C / FAN / HERM on the can. An inverter outdoor does not have this part.

  • CCommon — both windingsCap
  • FANOutdoor fanCap
  • HERMCompressorCap

Landing

  • 24VIndoor Rstat R

    ~24 VAC hot

  • 24VIndoor Cstat Coutdoor C

    Common. Outdoor will not pull without it.

  • 24VStat Yindoor Youtdoor Y

    ~24 VAC across Y–C at the contactor under a call

  • 24VStat Gindoor G

    Indoor blower. Does not go outdoors.

  • LineL1 / L2disconnectcontactor line

    208/230

  • CapCap C / FAN / HERM

    Both sections vs the can stamp

Prove it

  • 24 VAC across outdoor Y and C under a Y call, measured at the outdoor.
  • Contactor pulls and stays. Chatter is low 24V, a cooked coil, or HPS in series.
  • Dual-cap FAN and HERM both in spec.

Do not

  • Do not land a ComfortBridge / ABCD / iComfort data pair on this outdoor. It wants Y and C.
  • There is no O/B. That screw is the heat-pump twin.
  • There is no Y2.

Field landing, not a scanned OEM schematic. Photograph the outdoor silk if the screws are not labeled Y/C.

Sequence

  1. 1

    Y

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

Faults on this IFC

Step 1, then 2, then 3. Expected reading and the fail branch sit under each check.

No Y

Outdoor silent

warn

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

  1. 1 Is Y actually at the contactor?

    On Goodman GLXS4B a silent outdoor is often no Y. Measure 24 VAC coil-to-C at the contactor on a cool call. Y and C at the outdoor. Indoor IFC / stat actually closing Y.

    Expect: ~24 VAC at the coil when the indoor is calling.

    If fail: Indoor Y / IFC / stat — not a capacitor.

  2. 2 Cap and the compressor windings

    Dual run cap: herm and fan MFD ±6%. Then windings. A bad cap with a good Y is still the first cheap part — but confirm MFD, do not guess. Contactor coil ohms. Do not confuse a furnace lockout with a dead outdoor.

    Expect: MFD on the can. Even windings. Fan and compressor both try.

  3. 3 Contactor and mechanical

    Pitted contactor, no mechanical close, or a welded contactor that never drops out. Replace the failed part; do not file contacts as a repair.

    Expect: Clean pull-in. Line voltage through to both loads.

Hum / no start

Cap / start

lockout

Compressor hums, outdoor fan may run.

  1. 1 Is Y actually at the contactor?

    On Goodman GLXS4B a silent outdoor is often no Y. Measure 24 VAC coil-to-C at the contactor on a cool call. Dual cap (fan and herm). Replace on values, not just a bulge.

    Expect: ~24 VAC at the coil when the indoor is calling.

    If fail: Indoor Y / IFC / stat — not a capacitor.

  2. 2 Cap and the compressor windings

    Dual run cap: herm and fan MFD ±6%. Then windings. A bad cap with a good Y is still the first cheap part — but confirm MFD, do not guess. Hard-start only after the cap and windings are proven.

    Expect: MFD on the can. Even windings. Fan and compressor both try.

  3. 3 Contactor and mechanical

    Pitted contactor, no mechanical close, or a welded contactor that never drops out. Replace the failed part; do not file contacts as a repair.

    Expect: Clean pull-in. Line voltage through to both loads.

HPS

High pressure

lockout

Outdoor airflow, overcharge, or restriction.

  1. 1 Heat rejection first

    On Goodman GLXS4B high pressure is outdoor airflow until proven otherwise. Fan running the right direction, coil clean, fins not folded, no recirc over a fence or through a garage. Fan running? Coil dirty? SC vs nameplate on a TXV coil.

    Expect: OD fan on, coil clean, discharge air leaving the top/side freely.

  2. 2 Head, subcooling, and liquid line

    Liquid pressure and liquid-line temperature → SC. High head + high SC = overcharge or non-condensables. High head + low SC = restriction or a dying compressor. Do not add gas because suction is low.

    Expect: SC vs the metering device on this plate (TXV ≠ piston).

  3. 3 Restriction vs the switch

    Drier, liquid-line kink, TXV inlet screen, or a non-feed indoor coil will stack head. Ohm / jumper-test the HPS only as a momentary prove, then restore it. A switch that opens on a known-good charge and clean coil is the switch.

    Expect: HPS closed at a normal liquid pressure for this refrigerant and OD ambient.

LPS / freeze

Low pressure

lockout

Charge, indoor airflow, metering.

  1. 1 Airflow and freeze before you add gas

    On Goodman GLXS4B low pressure / freeze is indoor airflow or a starved coil until proven otherwise. Filter, blower, dirty A-coil, closed supplies. In heat mode, a iced outdoor coil is the same family. Do not add gas on a frozen coil. Indoor filter/coil first.

    Expect: Indoor air moving. Coil not iced. OD coil clear in heat.

  2. 2 SH / SC after a thaw

    Thaw fully. Then SH and SC vs the metering device. Low charge ices a piston. A TXV stuck closed ices with high SH. A restriction downstream of the ports fakes a low-charge chart.

    Expect: SH/SC in range for this refrigerant and device after a stable 10-minute run.

  3. 3 Leak, TXV, then the LPS

    Weigh-in if the chart says undercharge. Soap / electronic leak on joints and the coil. LPS that opens on a known-good charge and a clear coil is the switch — momentary test only, then restore.

    Expect: Charge on the nameplate. LPS closed at a normal suction for this OD ambient.

Workflows

No cool, GLXS4B

Indoor running, outdoor dead, plate says R-32.

  1. 1 Prove the call and the live code

    This is 24V Y. There is no ComfortBridge outdoor and no inverter to reset.

    Expect: Write whatever Contactor + fan — R-32 nameplate, no communicating outdoor PCB is showing. Nothing to recall. Watch the contactor and the R-32 pressures.

    If fail: No call at the IFC → stat / harness. Do not change gas parts.

  2. 2 Isolate the first failed step in the sequence

    24 VAC across the contactor coil. Then dual cap, then R-32 pressures.

    Expect: The first dead output or open prove.

  3. 3 Confirm with a number, then the next part

    Charge: piston = SH, TXV = SC, on the R-32 chart for THIS outdoor — not GSX16 410A targets. Leak repair: recover R-32, repair, pressure-test, weigh-in + line-set. Do not top off 410A into this cabinet.

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

    If fail: Stay on this plate. The out-of-range reading is the part.

    If pass: Reading in range → the next step in this workflow is the repair.

Test points

Charge

Nameplate + line-set. SH on piston, SC on TXV.

Cap

Dual can. Fan and herm both in spec.

Gotchas

  • Techs treat every Goodman box as 410A GSX16. Read the plate. R-32 machines and cylinders only.
  • GLXT7C is the two-stage R-32 cousin — Y1/Y2, not this single contactor.
  • Amana ALXS4B is the badge twin. Same R-32 story.

Related plates

Install this plate

Install Goodman GLXS4B as R-32 single-stage · contactor + dual cap.

R-32 single-stage · contactor + dual cap

This plate — not the sister SKU

  • Not GSX16 / GSX14 (R-410A). Not GLXT7C (R-32 two-stage). Not GXV9S inverter. Not GSZC / GSZ heat pump.
  • Techs treat every Goodman box as 410A GSX16. Read the plate. R-32 machines and cylinders only.
  • GLXT7C is the two-stage R-32 cousin — Y1/Y2, not this single contactor.
  • Amana ALXS4B is the badge twin. Same R-32 story.

Control on this outdoor

  • No 7-seg on this outdoor. Indoor E2 is the furnace.
  • HPS / LPS (when equipped) open the contactor coil.
  • Rating plate says R-32. A 410A gauge set and a GSX16 charge chart are the wrong book.

Hardware

  • Refrigerant: R-32 (A2L). Recover / weigh on an R-32 machine. Do not mix 410A.
  • Stages: Single-stage scroll · one contactor
  • Metering: Indoor TXV / piston per the R-32 coil match — not a leftover 410A piston
  • Pair: 24V Y from any conventional furnace / AHU
  • Sister SKU: GLXS4M multi-family 1.5–3 t · GLXS5B 16.5 · GLXS3B 15 · Amana ALXS4B

First fire

  1. 1This is 24V Y. There is no ComfortBridge outdoor and no inverter to reset.
  2. 224 VAC across the contactor coil. Then dual cap, then R-32 pressures.
  3. 3Charge: piston = SH, TXV = SC, on the R-32 chart for THIS outdoor — not GSX16 410A targets.
  4. 4Leak repair: recover R-32, repair, pressure-test, weigh-in + line-set. Do not top off 410A into this cabinet.

Do not on Goodman GLXS4B

  • Not GSX16 / GSX14 (R-410A). Not GLXT7C (R-32 two-stage). Not GXV9S inverter. Not GSZC / GSZ heat pump.
  • Techs treat every Goodman box as 410A GSX16. Read the plate. R-32 machines and cylinders only.
  • GLXT7C is the two-stage R-32 cousin — Y1/Y2, not this single contactor.

Maker literature

FieldBench does not host manufacturer files. Each link opens the maker’s own literature page in a new tab.

  • Goodman literature libraryLiterature searchSearch the exact plate (GR9T960804CN, GR9S960603BN). Full I/O PDFs are often dealer-gated.Open manufacturer PDF
  • Goodman literature libraryLiterature searchSearch Goodman GLXS4B on the maker’s literature page.Open manufacturer PDF

Warranty and bulletins

Affected models, serial range, symptom, remedy, date. Maker files open on the manufacturer site.

All bulletins

  • Dealer portals

    dealer

    Where remaining service letters live

    Current-year service letters not on a public literature page · Maker dealer portal

    Open factsOpen manufacturer PDF