How To Replace an Intermatic T104 Clock Motor

Written by:  Danny Rhodehamel

The clock motor in an Intermatic T104 timer will occasionally fail. It is time to replace the mechanism if the yellow wheel stops turning but the manual switch still functions correctly. The following steps will provide a guide on how to replace the WG1573-10D.

Tips & Warnings

Things You'll Need

Step by Step

Step 1

TURN OFF THE POWER TO THE TIMER BOX. There should be a circuit breaker before the timer box where the power can be turned off.

Step 2

Inside the Intermatic T104 box, remove the black plastic insulator. The insulator is held in place by one screw.

Step 3

With a flathead screwdriver, loosen the screws that hold the ground cables and power cables in place. Pull the cables away from the Intermatic mechanism.

Step 4

Compress the tab at the top of the box that holds the mechanism in place.

Step 5

Pull the Intermatic T104 mechanism out of the box.

Step 6

Place the T104 mechanism on a smooth flat surface with the yellow clock dial facing up. Remove the two screws, from terminals 1 and 3, that secure the two white clock motor cables in place.

Step 7

Turn the mechanism over to the backside and locate the clock motor.

Step 8

With a small phillips head screwdriver, remove the two screws the fasten the clock motor to the mechanism.

Step 9

Remove the clock motor and white cables from the Intermatic T104 mechanism.

Step 10

Place the new Intermatic WG1573-10D clock motor onto the mechanism. Align the holes on the clock motor with the holes on the mechanism.

Step 11

Tighten the two screws and fasten the clock motor to the T104 mechanism.

Step 12

Feed the white cables from the clock motor through the cable holder on the mechanism.

Step 13

Turn the mechanism over and place one white cable onto terminal 1 and the other onto terminal 3. It does not matter which white cable goes to terminals 1 or 3.

Step 14

Tighten the two terminal screws to terminals 1 and 3.

Step 15

Press the T104 mechanism back into the timer box.

Step 16

Connect the ground wires to the green screw located on the Intermatic timer mechanism. The ground wires will be green or exposed copper. One ground will be coming from the breaker and the other will be from the equipment.

Step 17

Locate the two input power cables that come from the breaker. Connect one to terminal 1 and the other to terminal 3. Terminals 1 and 3 are called the "Lines". Note: it does not matter what color goes to 1 or 3. It only matters that one cable is on 1 and the other is on 3.

Step 18

Connect the cables running from the equipment to terminals 2 and 4. One cable will go to teminal 2 and the other to terminal 4. Terminals 2 and 4 are called the "Loads". The Loads are what the timer controls. Note: it does not matter what color goes to 2 or 4.

Step 19

Place the black plastic insulator back into the box and tighten the screw to keep it in place.

Step 20

Turn on the power at the circuit breaker.

Step 21

The Intermatic WG1573-10D clock motor should now be successfully installed if the yellow clock dial is turning. Close the timer door and continue to enjoy the energy savings of using a timer.

Comments (1 to 15 of 15)

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User: Inyopools

jwaer - Sounds like the dial is turning correctly, just that the ON tripper isn't engaging. Check that the ON tripper is installed correctly. See our guide on "How To Install an Intermatic T104 Timer". Does the on/off toggle switch under the dial, left upper corner, switch back and forth as it engages with the ON tripper and OFF tripper?

User: jwaer

I replaced the timer motor, the timer is keeping perfect time but when it comes time to turn on it won't turn on. is the unit it self shot?

User: Inyopools

Question - I would guess that your motor is a 220V motor if the gears are moving but I would check the supply voltage just to be sure. Your problem may be in the gears of the timing mechanism that the motor is driving. Take the motor off of the back of the timing mechanism and turn the dial by hand to see if the small gear in the back that the motor engages move. If it does, maybe the gears are worn and are binding when driven by the motor? You may need to buy a new timer mechanism. Also your problem may be as simple as the dial was not engaged with the gears. It has to seat into the gears after you pull it out to set the time.into the gears after you pull it out to set the time.

User: Question

i replaced the motor on my intermatic timer. It's an old house and an old timer, and the information on what tYpe of timer it was (220 or 110v) was unknown. The gears move on the new motor, but the dial does not turn. Is it possible I ordered the wrong voltage motor and its not turning the gears? I bought the 1573-10d 208/277 hz. Of course I threw out the old motor when I hooked it up and saw the gears moving and assumed the dial would move too. Could this be the problem? Should I get a volt meter to test it? Or is something else wrong?

User: Inyopools

T104 Clock Motor - It sounds like one of your motor wires is going to a load line. Recheck the motor wiring against the picture in Step #17. The motor wires should be connected to the input terminals 1 and 3. Note: the first terminal is not labeled. Also check that you have 240V coming into the timer. Your T104 Clock motor is a 240V motor. T101 is a 120V motor.


I just installed a new motor and it seems to work fine when the timer is switched on. I see the gears moving as they should. However when the timer is in the off position, there is no gear movement at all which means the clock isn't moving. I tested the lines with a non contact tester and they are live in both states (on and off). Any ideas on what the problem could be? Thank you!


These were extremely helpful. Fairly inexpensive repair and easy to do. Like Pablo, I also needed a small star screwdriver to remove the old motor from the back of the timer.


Great directions. Thank you!


Thank you for the help. Great job!


Extremely useful. Even though my timer was not wired exactly as the one in the instructions, I was able to figure out how to do the job.


This was a piece of cake. Only cost me $25 for the part. Thanks for the instructions.

User: CB

Perfect instructions, even a girl did it!!!

User: Inyopools

Pablo - Thank you. We really appreciate your added insights.

User: Pablo

Great review. Dead easy even for the mechanically challenged. A few additional hints. There is a small port at the right above the yellow clock face. A flashlight will show the gears. If the power is on and the gears are not turning it is most likely the motor. I ordered a WG1573-10D. The old motor was a WG1575-5 and so was the new one. This is a 208/277v motor. There is a replacement for a 110 system also. Finally my screws were not phillips but one with star heads. None of the phillips screwdrivers I had would fit. I had a special star screwdriver to match. There was a lateral slot for a small flathead screwdriver. This should not inhibit anyone but just be careful to use the right screwdriver.

User: Mrs. Faniaska

Thank you for these instructions. I was able to do this myself. Regarding the power, it's good to mention that there are two boxes on the house, one for the 110 volts and the other for the 220 volts. It is likely the intermatic will be connected to the 220 volt box. Find the breaker there. Some of us are "handyman" challenged. :)

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