Check Your Door First
With the door closed, pull the emergency release cord and lift the door to see if it opens and closes smoothly. If it doesn't, the problem is with your tracks, rollers or springs rather than your opener. Learn more about garage door tune-ups.
Play it Safe
Unplug the opener. That way, you won't lose a finger if your unsuspecting housemate hits the remote button while you're working. Even worse, you could electrocute yourself, in which case you wouldn't be able to blame your housemate at all.
Symptom: The Remote Works But the Wall Switch Doesn't
Fix: Replace the wall switch and wires
If the remote works but the wall switch doesn't, you may need to replace either the wall switch or the switch wires. To determine whether the switch or the wires are bad, first unscrew the switch from the wall and touch the two wires together (don't worry, the wires are low voltage and won't shock you). If the opener runs, you have a bad switch. If you have an older-model opener, a cheap doorbell button might work. If you have a newer opener that has a light and a locking option on the switch, buy the one designed for your model. A new one should cost you about $15.
If the opener doesn't run when you touch the wires at the opener, use a small wire and jump those same two wires at the opener terminal. If the opener runs, the wire that connects the opener to the switch is bad. Sometimes the staples that hold the wire to the wall pinch the wire, causing a short. Install 18- to 22-gauge wire.