6 EASY Steps To Bypass Any Thermostat

Dominic Mitton
By Dominic  • Reviewed by Ben  • Updated:   October 19, 2023
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If you suspect that you have a faulty thermostat and you don’t have a multimeter to test it out, the best way to do so is to bypass the thermostat.

This is a very easy process and very safe, so you can do it all by yourself.

Pay attention to each step and you’ll get it all done in under 7 minutes.

6 Easy-To-Follow Steps To Bypass The Thermostat

1. Cut the power off

Most heating and cooling systems are powered by 240-volt breakers, so it’s important that you turn it off before starting anything.

Some systems might have a furnace, blower, or air conditioner, but all of them have a breaker in the electrical panel that you can easily shut off.

2. Remove the cover plate

Use a screwdriver to remove the cover plate by twisting slightly to pop off the faceplate.

Then you’ll have to remove the mountain screws that are responsible for protecting sensors.

Once you’ve done it, you just have to remove that sensor and expose the thermostat wires.

3. Check the wires

You should check the wire for the color code.

We explained each color code in this thermostat wiring guide.

If you have a five-wire thermostat, the terminals will be stamped with C, G, Y, W, and R.

Let’s break down each color and what it does.

C means common and the color is usually blue or black, depending on the model of your thermostat.

G is green and the job of this wire is to control the blower motor.

Y is yellow and controls your cooling system. W stands for white and it’s only made for heating systems. And R is for red and it supplies the power to the thermostat.

4. Choose the wire

First, you’ll use the red wire to supply power directly to one of the other wires – except for the common wire which is blue or black.

You should never touch the red wire and common wire together.

In my opinion, you should start with the green wire as it controls the blower which you can hear if it’s running or not.

However, if you have a 3-wire thermostat, always go with the white wire first.

5. Twist the wires

Now that you chose the wire you’ll combine it with the R wire, twist them both and turn the breaker on.

If you choose the green wire (as I always recommend), you should hear the blower starting as soon as you flip the breaker.

If you choose the yellow or white wire, you should hear either the furnace or the air conditioning system starting.

You’ll have to repeat this same procedure for each wire (except the common – blue or black). This is done because if the blower or air conditioner unit doesn’t start, you can know exactly which component is faulty.

If that’s an issue, you’ll most likely have to seek professional help.

6. Finish the test

Untwist the wires and align them in their starting position.

If you don’t have a thermostat yet, just make sure to separate the wires.

Put the cover plate again and make sure you’ve returned your thermostat to how it looked before.

All of these steps are explained in-depth in this video.

Congratulations, you’ve just saved yourself a couple of bucks and done everything by yourself instead of hiring a technician.

Hey there! I am Benas, the founder and content editor at Home Caprice. Thanks for reading the article. I hope you were able to find what you were looking for. I and my team are here to simplify heating and cooling for everyone. Please have a look at the About page for more details about our website and feel free to check out our editorial process.