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Mike, Master Electrician
Category: Electrical
Satisfied Customers: 1425
Experience:  Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
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I want to test a garage door motor assembly that I've

Customer Question

I want to test a garage door motor assembly that I've removed from its casing. The motor has white, red and blue wires coming from it. I assume that the white is common. The red and blue wires run from a capacitor, and that capacitor is fed by another set of red and blue wires that I assume provide power to into the capacitor.
When mounted in the case anc controlled by the garage door opener control panel, the motor showed no life when the opener was activated by the push button switch.
I'd like to provide 110 volts to the assembly as a bench test. I assume that the red and blue wires are for either CW or CCW operation of the motor. If I connect 110v to the white wire and either the blue or red that feeds power INTO the capacitor, the motor should operate -- correct? I just want to make sure this makes sense before I do it. I assume that bypassing the capacitor and supplying 110v to the red or blue wires running directly into the motor won't be successful.
Submitted: 11 months ago.
Category: Electrical
Expert:  ProGrade replied 11 months ago.

Hi Paul welcome to

Customer: replied 11 months ago.

What additional info do you need?

Expert:  ProGrade replied 11 months ago.

Sounds like there isn't a wiring diagram on the motor.

Do you know what the make & model of the unit is? I will see what I can find.

I wouldn't recommend apying power to it until you are certain what goes where.

Do you have a multimeter?

Customer: replied 11 months ago.

I do have a multi-meter.

Expert:  ProGrade replied 11 months ago.

Do you have the housing that the unit mounts in? Are there any clues there? Terminal strips, etc?

Make & model would be good thanks

Customer: replied 11 months ago.

The Craftsman model number is(###) ###-####RT2

Expert:  ProGrade replied 11 months ago.

Thanks, ***** ***** try to find info.

Customer: replied 11 months ago.

Correction. The model number is *****

Expert:  ProGrade replied 11 months ago.

No success, I will opt out to give other experts the opportunity to pick up your question. Perhaps someone has more knowledge about the internal wiring.

You are on the right track...a common (neutral) wire and one wire to each winding for up and down (cw & ccw rotation). It sounds odd that the capacitor wiring is the same color as the motor leads.

Good luck with your project

Customer: replied 11 months ago.

OK, Don't give up yet. I decided to take a few chances since I was just going to throw the remnants away if they were bad anyway. So I confirmed 120 volts coming into the wiring mount block. From there the hot wire feeds into a 12-wire plug that mounts into the unit's logic board. The red and blue wires run from that same logic board plug and into the capacitor, so I assumed the logic board was nothing but a complicated switch board controlling the route of the electric.

I used a jumper from the hot wire at the mounting block to the input spade of the capacitor, and sure enough I could make the motor rotate CW and CCW by alternately jumping to the red and blue wires. So now I know that my motor is good, the capacitor is good, the limit switch assembly is good, and the speed sensor is good. I got a lot accomplished!

By process of elimination, I have to assume that the opener's logic board is bad. There really is no other module that could have failed -- there are no visible fuses. Do you agree?

Expert:  Matthew McDevitt replied 10 months ago.

Hello! Maybe i can help!

Expert:  Matthew McDevitt replied 10 months ago.

I would agree by way of elimination it sounds like board is bad. Be careful with directly connecting to the capacitor. Make sure you are wearing the proper personal protective gear.

Expert:  Joseph D'Albora replied 10 months ago.

I would have shot this the way you did. You did well, grasshopper. I am more familiar with HVAC control boards, but it sounds like you have little or nothing between your power source and the capacitor other than the board. You have confirmed the capacitor gets the motor turning and that the motor, in fact, turns.

If there are no other switches or safeties other than the board, I would most definitely replace the board. Confirm that you have nothing else (including remotes, wired or wireless) that could be breaking the control logic. If not, it's the board.