Goodmanac

GSX16

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.

Diagnose this model Install notes Board cross-ref Field wiring

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.

Nothing to recall. Watch the contactor and the pressures on this call.

Universal swap

No universal

No IFC. Contactor, capacitor, fan. Nothing in the WR/ICM furnace line belongs here.

White-Rodgers

—

ICM

—

Honeywell

—

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

After you pull the dead card

1Replace the failed contactor / cap / fan motor. There is no universal furnace board on this unit.

Field wiring

Written landings for Goodman GSX16. Not a factory schematic.

Single-stage 24V contactor

Conventional Y / CR-410A

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

Any 24V furnace / AHU. GR9T96 / GR9S96 land Y. GMVC 1/2 does nothing here.

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
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 Is Y actually at the contactor?
On Goodman GSX16 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 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 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 Is Y actually at the contactor?
On Goodman GSX16 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 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 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 Heat rejection first
On Goodman GSX16 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 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 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 Airflow and freeze before you add gas
On Goodman GSX16 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 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 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, GSX16, furnace is GR9T96 / GR9S96 / GMSS96

Indoor running, outdoor dead.

1 Prove the call and the live code
This pair is 24V Y. There is no ComfortBridge outdoor to talk to.
Expect: Write whatever Contactor + fan — no communicating outdoor PCB is showing. Nothing to recall. Watch the contactor and the pressures on this call.
If fail: No call at the IFC → stat / harness. Do not change gas parts.
2 Isolate the first failed step in the sequence
24 VAC across the contactor coil. Then cap, then pressures.
Expect: The first dead output or open prove.
3 Confirm with a number, then the next part
Charge: piston = SH. TXV indoor = SC. Do not mix those. If the indoor is GMVC96 on data wire, this outdoor still wants Y — data wire into a GSX16 does nothing.
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

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

Install this plate

Install GSX16 as a single-stage contactor + dual-cap AC. No outdoor PCB codes.

Single-stage scroll · contactor · dual run cap · piston or indoor TXV · 24V Y

Electrical & charge

Contactor coil from indoor Y. Dual run capacitor — fan and herm terminals. There is no ComfortBridge outdoor board.
Piston or TXV per the indoor coil. Charge method follows the metering device, not a two-stage weigh-in chart.
GSX14 / GSXN4 / GSXH5 are SEER-family siblings — same contactor story, different rating plate.

First fire

1Y: 24 VAC at the coil, compressor and fan run. If not, cap / contactor / LPS-HPS (when equipped).
2SH (piston) or SC (TXV) to the indoor/outdoor pairing, not a GSXC18 two-stage target.

Do not on Goodman GSX16

Do not look for a 7-seg on this outdoor. Indoor furnace E-codes are not this unit.
Do not land a data pair. There is nowhere for it to go.

Maker literature

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

GSX16 product pageProduct pageOpen manufacturer PDF
GSX16 specification sheetSpec sheetSearch this plate in the Goodman literature library.Open manufacturer PDF
Goodman literature libraryLiterature searchSearch Goodman GSX16 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 facts Open manufacturer PDF