What are the specs for this Wiring Harness?

The correct replacement for Goodman model GMN120-5 Furnace — B1378700 is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Goodman equipment which lists the model number GMN120-5 Furnace — B1378700.

What symptoms indicate I need a new wiring harness?

Common symptoms that indicate you need a new wiring harness include unusual noises, intermittent operation, complete failure to operate, or visible damage. For specific diagnostic guidance, visit nationalhvacparts.com/pages/hvac-diagnostic.

Is this wiring harness compatible with Bryant or Payne systems too?

Many Goodman parts are cross-compatible with Bryant and Payne systems since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across multiple brand labels with different model numbers. To verify cross-compatibility, check your Bryant or Payne equipment service manual for cross-compatible part numbers, or contact info@nationalhvacparts.com with your model number for confirmation.

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Goodman

OEM Goodman 16-Pin Wiring Harness for GMN120-5 Furnace — B1378700

Name: OEM Goodman 16-Pin Wiring Harness for GMN120-5 Furnace — B1378700
Brand: Goodman
SKU: GOODMAN-11591
Price: 18.95 USD
Availability: InStock

SKU: GOODMAN-11591 Brand: Goodman

$18.95 $24.95

OEM Guaranteed

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30-Day Returns

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Texas CMBL #19328542014

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The Goodman B1378700 16-Pin Wiring Harness is a genuine OEM replacement for GMN120-5 series gas furnaces. This factory-terminated harness carries power and signal between the integrated furnace control board and key components. Melted connectors, chafed insulation, or intermittent no-heat faults are classic signs a harness needs replacing.

Specifications

OEM Part Number: B1378700
Connector: 16-Pin
Type: Control Board Wiring Harness
Compatible Model: Goodman GMN120-5
Equipment: Gas Furnace

OEM vs. Generic

This genuine Goodman OEM harness arrives with the correct pinout, wire gauge, and keyed connectors already terminated — no crimping, guessing, or resistance mismatch. Generic aftermarket harnesses often require manual splicing that introduces failure points and voids diagnostic reliability. OEM guarantees a clean, code-compliant connection.

Installation Difficulty

Moderate (3/5). Straightforward for a comfortable DIYer but demands care. Kill power at the breaker, photograph the existing routing, then unplug the keyed connectors one at a time and transfer. Match the connectors exactly — never force a plug. Allow 20–30 minutes.

Backed by our fit guarantee. Questions? Contact info@nationalhvacparts.com.

Shipping Information

Orders placed before 3PM CST ship same business day
Standard delivery: 2-5 business days
Express shipping available at checkout
Free shipping on orders over $75
Tracking number emailed upon shipment

Return Policy

30-day returns on unused parts in original packaging
Electrical parts (capacitors, contactors, control boards) are final sale once installed
Email info@nationalhvacparts.com to initiate a return
Refunds processed within 5-7 business days

OEM Goodman 16-Pin Wiring Harnes...

$18.95

Frequently Asked Questions

Does this Wiring Harness fit my Goodman GMN120-5 Furnace — B1378700?

Yes. This is the factory-specified OEM wiring harness for the Goodman GMN120-5 Furnace — B1378700. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.

How do I replace the wiring harness on my Goodman GMN120-5 Furnace — B1378700?

Refer to your equipment service manual for model-specific steps. General approach: turn off power, photograph connections, remove old part, install new part, restore power and test. For gas components, hire a licensed technician. Email info@nationalhvacparts.com for guidance.

What symptoms mean I need a new wiring harness?

Common symptoms: unusual noises, intermittent operation, complete failure, or visible damage. Visit our diagnostic hub for symptom-based troubleshooting.

Is this wiring harness compatible with Bryant or Payne too?

Many Goodman parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.

Should I use OEM or aftermarket for my Goodman wiring harness?

OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.

How fast does National HVAC Parts ship?

Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.

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