Wired Wrong? How to Properly Connect the Thermostat to Your Goodman GLXS4BA3610 + AMST36CU1300

Introduction: The Small Wires That Control Everything

Here’s the thing: I’ve been called out to dozens of homes where the AC wasn’t cooling, and it turned out to be a simple thermostat wiring issue. It’s easy to overlook, but if you don’t wire the thermostat right, your whole Goodman system won’t know when—or how—to run.

If you’ve got the Goodman 3 Ton 14.5 SEER2 R-32 System—which includes the GLXS4BA3610 condenser and AMST36CU1300 air handler—you’ve already made a smart choice. Now let’s make sure the thermostat connection is just as solid.

 

1. Understand the Thermostat’s Role in Your HVAC System

Think of your thermostat as the brain of your HVAC setup. It tells the air handler when to blow and the condenser when to cool. It does this through a low-voltage control circuit—usually 24 volts—using small wires labeled R, W, Y, G, C, and sometimes O/B or AUX depending on the system.

If these wires are incorrectly installed, your system might:

• Fail to turn on

• Blow only warm air

• Run continuously

• Short cycle or trip breakers

And trust me, all of those are headaches you don’t want.

 

2. Thermostat Wire Color Codes and What They Do

Let’s break down the typical thermostat wiring:

Keep in mind, wire colors aren’t always followed. Always double-check both ends of the wire before assuming anything.

 

3. Wiring the Goodman GLXS4BA3610 + AMST36CU1300: A Step-by-Step Guide

This system is a straight cool air conditioner with a matching air handler, so the wiring is relatively straightforward. Here’s what you do:

✅ Step 1: Shut Off All Power

Kill the breaker to both the air handler and condenser. We’re working with low voltage, but it’s still best to be safe.

✅ Step 2: Open the Thermostat and Label Your Wires

Unscrew your thermostat faceplate and look for the wire terminals. Label each wire with tape if it’s not already marked.

✅ Step 3: Connect the Thermostat to the Air Handler

Use a 5-conductor wire (minimum) from the thermostat to the AMST36CU1300 air handler:

• R (Red) ➝ R

• C (Blue or Black) ➝ C

• Y (Yellow) ➝ Y

• G (Green) ➝ G

If you're using auxiliary electric heat, connect the W (White) to W1.

✅ Step 4: Connect the Air Handler to the Condenser

Now run a 2-conductor wire from the air handler control board to the GLXS4BA3610 condenser:

• Y (Yellow) ➝ Y (24V cooling signal)

• C (Common) ➝ C

This links the outdoor unit to the control signals passed from the thermostat.

✅ Step 5: Check for Jumper Wires or Dip Switch Settings

Some air handlers may require you to set a blower speed dip switch or jumper for fan operation depending on your thermostat's configuration (single-stage vs. multi-stage cooling). Refer to the installation manual for both components to be sure.

 

4. Thermostat Compatibility: Smart vs. Conventional

The Goodman GLXS4BA3610 + AMST36CU1300 system works with most conventional 24V thermostats—including programmable and Wi-Fi smart thermostats. But:

• If using a smart thermostat (like Nest, Ecobee, Honeywell T9), make sure you have a C-wire. If not, install a C-wire adapter or get a technician to pull a new wire bundle.

• Don’t enable heat pump settings—this isn’t a heat pump system.

More details on C-wire adapters can be found at Energy Star’s smart thermostat guide.

 

5. Testing the Thermostat: Don’t Skip This!

Once everything is connected and powered back on:

1. Set the thermostat to Cool Mode and lower the setpoint.

2. Listen for the air handler to start blowing.

3. Walk outside—the condenser should kick on a few seconds later.

4. Check that the blower speed matches expected CFM, and no error codes are blinking on either unit.

If the condenser doesn’t run, double-check the Y and C wires. If the blower won’t start, check the G wire and the fan delay timer.

Pro tip: If you’re not getting 24V between R and C, you’ve got a transformer issue or a blown fuse on the air handler’s control board.

 

6. Mistakes to Avoid When Wiring a Thermostat

Let’s save you a callback (or a future service charge):

• Don’t reverse Y and W—your system will try to heat instead of cool.

• Don’t leave the C-wire disconnected on smart thermostats.

• Don’t forget to tie in the condenser’s common wire (C) to the same common as the air handler—or you’ll fry the transformer.

• Don’t mismatch stages (ex: using a 2-stage thermostat with a 1-stage unit without configuring settings).

 

7. When to Call an HVAC Pro

Wiring a thermostat isn’t always plug-and-play—especially when you're dealing with older wiring, missing wires, or smart thermostat integration. If you:

• See arc flashes or burn marks

• Have no 24V at the thermostat

• Hear loud buzzing or clicking from the control board
  ...it’s time to step back and call a licensed HVAC tech.

A botched thermostat connection can short your transformer, overwork your compressor, or blow control fuses—none of which are fun or cheap.

 

Final Thoughts: A Little Wire Goes a Long Way

Getting the thermostat wiring right on your Goodman GLXS4BA3610 + AMST36CU1300 system isn’t just about comfort—it’s about safety, efficiency, and maximizing the value of your investment. Whether you’re a DIYer with experience or just want to double-check your HVAC tech’s work, understanding the wiring basics can save you from a world of trouble.

If you're looking to purchase or need detailed specs for the Goodman GLXS4BA3610 air conditioner condenser and AMST36CU1300 air handler, you can find them directly at The Furnace Outlet’s official product page. Their team can also help answer installation-related questions if you're not sure where to start.

Are you dealing with low airflow? Visit my guide: Set the DIP Switches Right on the Goodman GLXS4BA3610 + AMST36CU1300.

And remember—when in doubt, bring in a pro. Correct wiring today can mean years of smooth cooling tomorrow.

Until next time,

- Samantha, Home Comfort Advisor