Garage door stuck and won't open: what to check first

A stuck door is a symptom, not a fault, and the useful question is which half of the system has failed. The door and its counterbalance are one half. The opener is the other. Five minutes of checking separates them, and it decides whether this is a part or an adjustment.

Start by disconnecting the opener

With the door closed, pull the red release cord hanging from the rail. That disconnects the trolley from the opener and puts the door on manual. Now lift it by hand.

If it will not lift, or feels enormously heavy, the problem is the door: a broken spring, a cable off its drum, or something jammed in the track. Stop there. If it lifts smoothly and stays put at waist height, the door is balanced and the problem is the opener.

If the door is the problem

Look at the spring above the opening for a gap in the coil. Look at both cables to see whether one has gone slack or come off its drum. Look down both tracks for a roller that has left the channel, and for anything sitting in the bottom of the channel. Any of those means leave the opener alone until it is fixed.

If the opener is the problem

A motor that runs while nothing moves is usually a stripped gear kit, or a trolley that has come off the carriage. A motor that does nothing at all is power, the wall button, the logic board, or a capacitor. A door that starts down and reverses is the photo eyes or the down force. A door that stops at the same point every time is the travel limit, and it is an adjustment.

Winter adds one more

A rubber bottom seal will freeze to a concrete slab, and an opener asked to break that bond will strip its gears or pull the bottom bracket out of the door before it lets go. If the door will not start moving on a cold morning and the springs look fine, check the seal before pressing the button again. Keeping the slab clear of packed snow and ice through the winter is the cheapest prevention there is, and the guide to garage door weather stripping covers what a season of freezing rain does to that seal.

The seal material matters as well. Natural Resources Canada's weatherstripping guidance warns that some products get hard, and less effective, in cold weather, when you need them most, and says to look for ones that are flexible and spring back to their original shape quickly.

What ties all of these together is the same rule: if the door has not moved after two attempts, stop. Nearly every expensive garage door repair started as a cheap one that somebody kept pressing the button on.