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 6 of 6)

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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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