How Local Conditions Play In
Most houses on this side of Northbrook were built between 1938 and 1996, with the typical build year landing around 1974. That matters more than people think, because photo-eye safety sensors weren't standard equipment on garage doors from that era. In a huge share of the homes we get called to - and that holds across the 61 named areas we cover, where the stock is overwhelmingly 1960s and 70s construction - the sensors you see bolted a few inches off the slab are retrofits, added to a track system that was never designed around them.
That's the first piece. The second is the cold, moderate climate band this area sits in. Frost heave and seasonal freeze-thaw cycles move concrete slabs and wood door jambs a little every year - not enough to notice day to day, but enough over a decade or two that a bracket mounted flush in 1985 is no longer flush today. Sensors don't fail because the electronics wear out. They fail because the wall around them moved and the sensor didn't move with it.
What Most People Get Wrong
The common assumption is that a blinking opener light or a door that won't close means the sensor itself is broken. Most of the time it isn't. On homes from the 1960s-70s era that make up most of this area's housing stock, the more common problem is that the bracket holding the sensor has crept out of alignment - sometimes from that slab and jamb movement, sometimes because someone bumped it with a bike or a snow blower over the years and never noticed the eye was now pointed a few degrees off.
People also assume a wipe with a cloth fixes drift. Dust and cobwebs do block the beam, and it's worth checking first. But if the lenses are clean and the door still won't close, or closes and immediately reverses, that's alignment or wiring, not dirt. Chasing the wrong cause means swapping sensors that were never broken, and a retrofit bracket loosely screwed into old jamb wood can work itself crooked again within a season regardless of how many times you replace the unit.
When to Get Help
If the lenses are clean, the small indicator lights on each sensor are solid rather than blinking, and the door still won't close, that's past what a homeowner can fix by re-aiming a bracket by eye. It's a call. Same if the door closes fine some days and not others - that pattern points to a marginal wiring connection, not a dirty lens, and it tends to get worse, not better.
One honest limit: if the bracket itself has rotted out of the jamb wood, common enough in a house pushing 60 or 70 years old, a new sensor won't hold alignment any better than the old one until the mounting surface is solid. Sometimes that means a small wood repair before the sensor work makes sense, and that's worth knowing before you pay for a part swap that won't stick.
