How to Replace a Halogen Light Transformer

Two halogen light bulbs on a reflective white surface.
  • 2 hours
  • Intermediate
  • 45
What You'll Need
Basic socket and wrench set
Wiring pliers
Replacement transformer
Masking tape
Wiring nuts

While halogen lights are not as energy efficient as LEDs, you may still have some you wish to keep even after a transformer stops working. This is a basic electrical task that doesn't require any special skills, and by doing it yourself, you can save time and money. So, if the lamp or fixture is important to you and you want to repair it, then follow the basic steps below and save the electrician for more complex tasks.

Step 1 - Remove the Power Source

The first and most important step when working with anything electric is to remove the power source; simply turning the switch to the "off" position, or flipping a light switch off, is not enough. If the light plugs into an outlet, then disconnect it. On the other hand, if it is wired inside a terminal box, find the breaker that it's on and turn it off. The power source must be completely disconnected to prevent any chance of electrical shock.

Step 2 - Find the Transformer

The part you're looking for can be found in various places with the majority of them being at the end of the wire that goes into the unit. In order to access it, you have to remove the cover plate. Some units will even have to be removed from mounting brackets in order to get to the transformer. In the event that this part is not at the end of the wire, look along the length of cord or at the base of the bulb. If you still cannot locate it, then your halogen light may not have a transformer installed in it at all. Obtain a wiring diagram of your specific unit instead and consider other types of repairs.

Step 3 - Remove the Transformer

After you have found the transformer, disconnect the wiring. Unscrew any bolts or screws holding it in place as well, and take the unit out.

Step 4 - Install the Replacement

Before purchasing the new light transformer, compare it with the old one to ensure that it is exactly the same model with the same voltage and amperage ratings. This way, you don't have to fuss with taking it back because you bought the wrong one. When the transformer is not designed for the light that you are working on, it will not work properly, if it works at all.

Bolt or screw the new part into place if needed, and then match the wiring colors with one another and cap the ends with wiring nuts. If the wires are not colored, make sure to mark each wire with masking tape and a marker as you take the old transformer out.

Step 5 - Put the Light Back Together

Once the new transformer is in place and wired correctly, test it with a multimeter to be sure it is working. Then, put the wiring cover plate back on and reinstall the unit if you had to take it off of the mounting brackets.

Taking the time to install your own halogen light transformer is an easy process and can save you a substantial amount of money. Again, when attempting this task be sure that before you begin the power source is completely taken away from the light. Electricity, as the saying goes, can kill, so always take precautions to be safe.