When an automatic gate stops working, the cause is almost always one of about a dozen common problems. Here's the troubleshooting checklist our techs run on every service call — what to look for, what's safe to check yourself, and what needs a professional. Use this before you call; sometimes a 30-second fix is all you need.
1. Gate Won't Open Or Close At All
Start with power. Check the breaker, the disconnect switch (if your operator has one), and the battery backup status light. PG&E PSPS events take many Marin gates offline; a dead battery backup looks identical to a dead operator.
2. Gate Opens But Won't Close
Almost always a safety sensor. Walk to each photo-eye, wipe the lens, look for cobwebs, and check that the red and green LEDs match the alignment instructions for your brand. A misaligned beam tells the operator something is in the path.
3. Gate Closes Then Re-Opens
Same family as above — the operator is sensing an obstruction. Look for sticks, leaves, gravel under the gate, or anything blocking the photo-eye beam at closing height.
4. Remote Doesn't Work
Replace the battery first. If that doesn't fix it, the receiver in the operator may need reprogramming. Rolling-code remotes occasionally drop sync after long inactivity.
5. Keypad Doesn't Work
Check keypad battery (wireless) or wiring (wired). Salt air corrodes terminals; a quick visual inspection often reveals the problem. Reprogram codes if the controller was recently reset.
6. Gate Moves Slowly Or Jerks
Lubrication. Sliding gate rollers, swing gate hinges, and chain drives all need grease. A jerky slider often means worn V-track wheels or debris in the track.
7. Loud Grinding Or Squealing
Stop using the gate. Grinding is metal-on-metal wear that gets worse fast. This is a call-now situation — continuing to cycle the gate can destroy the operator gearbox.
8. Intermittent Operation
Often a failing capacitor or a board issue. If the gate works some cycles and not others, the operator is on borrowed time. Don't ignore it.
9. Free-Exit Loop Stopped Working
Gate not opening as you drive up to leave? The loop detector or the loop wire itself has failed. Wire failures are usually visible as a crack in the pavement where the saw-cut was made.
10. Gate Drifts Or Sags
On swing gates, this is hinge wear or post movement. On sliders, it's worn rollers or a bent track. Both are mechanical issues that need adjustment or part replacement.
11. Strange Behavior After A Storm
Lightning and power surges fry control boards and receivers. If your gate started acting strange the morning after a storm, the board may be damaged even if it appears to work.
12. Gate Operator Hums But Doesn't Move
Almost always a failed start capacitor. Inexpensive repair, but the capacitor must match the operator spec — don't substitute.
When To Stop Troubleshooting
Anything involving the control board, motor, capacitors, or 120V wiring should be left to a professional. Automatic gate operators can move with significant force; opening the cover with the gate energized is genuinely dangerous.
Stuck? Al's Automatic Gate diagnoses and repairs all major automatic gate systems across Marin County. Open daily 7 AM – 8 PM. Call (415) 942-6409 for service.