A garage door that refuses to close fully — reversing at the last foot, stopping mid-travel, or bouncing back up — leaves your home insecure, lets pests in, and wastes heating and cooling energy. The good news: in 9 out of 10 cases, the cause is one of three simple, fixable problems you can diagnose in ten minutes with no special tools.
This guide covers every common cause for sectional garage doors (the type in 95% of Bay Area homes), the right order to troubleshoot, when DIY is safe, and what professional repair costs in 2026.
The Three Most Common Causes
- Misaligned or blocked safety sensors (60% of all cases)
- Wrong close-limit setting on the opener (25%)
- Worn rollers, bent track, or broken spring (15%)
Cause 1 — Safety Sensor Misalignment
Federal law has required photoelectric sensors near the floor on every garage door opener since 1993. They're the small boxes 4–6 inches above the floor on each side of the door. If the beam between them is broken, blocked, or even slightly misaligned, the door reverses or refuses to close.
How to Diagnose
Look at the LEDs on each sensor. Both should glow steady (typically green on the receiver, amber/red on the sender). A flashing or dark LED means the beam is broken, blocked, or the sensor is misaligned.
How to Fix
- Wipe both lenses with a soft cloth — spider webs and dust are #1 culprit
- Loosen the wing nut and gently re-aim until both LEDs go solid
- Check for objects (rake, bicycle wheel, leaves) blocking the beam
- Inspect the wires for staple damage or rodent chewing
Cause 2 — Wrong Close-Limit Setting
The opener uses a 'close limit' switch to know when the door has reached the floor. If it's set too high, the door senses an obstruction (the floor) before reaching the limit and reverses. Common after a power outage, a new opener install, or aggressive force adjustments.
Adjusting the Close Limit (most openers)
- Locate the two adjustment screws or buttons on the opener motor housing
- Look for the one labeled 'Down' or 'Close'
- Turn the screw 1/4 turn clockwise to allow the door to travel further down (or use the +/- buttons on newer LiftMaster/Chamberlain models)
- Test, repeat in small increments until the door seals against the floor without reversing
Cause 3 — Mechanical Problems
Bent Track
A car bumper, errant ladder, or settling foundation can bend the vertical track. Look for shiny rub marks on the rollers or visible kinks. Minor dents can be tapped straight; significant damage requires track replacement ($150–$350 per side installed).
Worn or Broken Rollers
Old steel rollers seize up, causing binding. Replace all 10 with sealed nylon rollers ($35 –$80 in parts, plus labor). The door will run dramatically quieter.
Broken Torsion Spring
If the door feels extremely heavy by hand, or you see a visible gap in the spring above the door, do not attempt DIY. Garage door springs store enough energy to break bones. Call a pro.
Step-by-Step Troubleshooting Order
- Disconnect the opener with the red emergency cord and lift the door by hand. If it's heavy or won't stay open at waist height, the spring is failing — stop and call a pro
- Inspect both safety sensor LEDs
- Clean the sensor lenses
- Realign the sensors until LEDs are solid
- Look up the track for bends or rub marks
- Adjust the close-limit setting in small steps
- If still failing, call a professional
DIY vs. Professional
Safe DIY: sensor cleaning, sensor alignment, limit-switch adjustment, lubrication. Call a pro for: spring replacement, cable replacement, track replacement, opener motor failure, anything involving disassembly above shoulder height.
2026 Repair Cost Estimates (Bay Area)
| Repair | DIY | Professional |
|---|---|---|
| Sensor alignment | $0 | $95–$150 service call |
| Replace photo sensors | $25–$50 | $175–$275 |
| Limit switch adjustment | $0 | $95–$150 |
| Roller replacement (full set) | $35–$80 | $175–$325 |
| Torsion spring replacement | Not safe | $275–$475 |
| Cable replacement | Not safe | $200–$350 |
| New opener install | — | $450–$750 |
Prevention
- Lubricate rollers, hinges, and springs every 6 months with white lithium grease (never WD-40)
- Vacuum sensor lenses quarterly
- Tighten all visible nuts and bolts annually
- Test the auto-reverse by placing a 2x4 flat under the door — it should reverse on contact
- Replace rollers proactively at 10 years
When to Call a Bay Area Professional
Call us if you've tried the steps above without success, suspect spring or cable damage, or want a full safety inspection. Our handyman team services San Jose, Sunnyvale, Cupertino, and the surrounding Peninsula.
FAQs
Why does my garage door close then reverse?
Either the close-limit is set too high or the safety sensors are slightly misaligned. Address sensors first.
How do I reset my garage door opener?
Unplug for 30 seconds, plug back in, then re-program the limits per the owner's manual.
Can rain or sun affect garage door sensors?
Yes. Direct sunlight on the receiver lens at sunset is a common false-trigger source. Add a small sunshade or rotate sensors slightly.
How long do garage door springs last?
Standard springs are rated for 10,000 cycles — about 7 years of normal use. High-cycle springs last 20,000+.
Is it safe to use a garage door with a broken spring?
No. The opener will burn out and the door can fall. Use the manual lock until repair.
Get Your Garage Door Working Today
Call (510) 938-4277 for same-day garage door diagnosis and repair, or learn more about our home repair services.
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