How to Repair a Garage Door Limit Switch

Buying new parts for an old, malfunctioning garage door opener can be an expensive guessing game if done on your own. Sometimes the problem seems to be some kind of “catch” in the device. It keeps the motor from either fully closing or opening the garage door. Let the team at Starlite Garage Doors walk you through an easy fix!
1. Check for Corrosion on the Switch Contact
This is the first thing to look at when the door seems to keep pulling up when opening or continues pulling down when closing. Corrosion will cause a mixed message to be sent to the sensor. If you notice the switch contact is no longer shiny, it will need cleaning.
2. Unplug Door Opener
Close your garage door. Take the plug out of the electrical socket and use your multimeter to test electrical contacts. The reading should show zero volts.
3. Locate the Two Limit Switches
They are usually small and boxy looking and are often rectangular shaped. They have prongs extending from one end. Take pliers in hand to remove the spade terminals from the top of the switch.
4. Test the Switches
Use a multimeter to check for continuity.If it shows no continuity between the two terminals on the switch, this is correct. If you then push the switch button, and the meter shows a continuity, the switch is working correctly. If it does not show a continuity, the switch needs cleaning.
5. Remove the Switches
Use pliers to pull the terminals from the switches. Do this delicately so you do not pull too hard on the wires connected to them. You will also have to remove the nut that attaches the switch to the opener.
6. Clean the Terminals
You should use a cotton swab and isopropyl alcohol to clean the three terminals. Then you should polish the metal with an emery cloth until the deposits are thoroughly removed. It could help to use electrical contact cleaner as well.
7. Further Cleaning May Be Needed
If the scrubbing of the terminals is not enough, you might also have to break into the enclosed switch with a putty knife. Continue to use the isopropyl alcohol to clean the metal parts until shiny. Reassemble the enclosure with a zip-tie. You should then clean the contacts on the garage door opener itself.
8. Reassemble and Test
After making sure all components are back in their original places, test the garage door opener. Try it several times to confirm correct action has been taken.
Call Us Today
If your self-repair does not do the job, we are here to help. Our team at Starlite Garage Doors is equipped to quickly analyze the problem and remedy the situation. We carry replacement parts for most brands.Our competitive pricing and professional repairmen make our work second to none. Call us now.