DEV Community: riseupgaragedoors The latest articles on DEV Community by riseupgaragedoors (@riseupgaragedoors). https://dev.to/riseupgaragedoors https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4023362%2Fc22ec120-28c6-4d49-ac7d-ed3c636b228c.webp DEV Community: riseupgaragedoors https://dev.to/riseupgaragedoors en Symptom vs Root Cause: What Fixing Garage Doors Taught Me About Debugging riseupgaragedoors Mon, 20 Jul 2026 14:31:35 +0000 https://dev.to/riseupgaragedoors/symptom-vs-root-cause-what-fixing-garage-doors-taught-me-about-debugging-5c2f https://dev.to/riseupgaragedoors/symptom-vs-root-cause-what-fixing-garage-doors-taught-me-about-debugging-5c2f <p>I&nbsp;run&nbsp;a&nbsp;garage&nbsp;door&nbsp;company,&nbsp;and&nbsp;the&nbsp;job&nbsp;is&nbsp;closer&nbsp;to&nbsp;debugging&nbsp;than&nbsp;people&nbsp;expect.&nbsp;The&nbsp;most&nbsp;common&nbsp;call&nbsp;goes&nbsp;like&nbsp;this:&nbsp;"the&nbsp;door&nbsp;will&nbsp;not&nbsp;close,&nbsp;and&nbsp;the&nbsp;opener&nbsp;light&nbsp;just&nbsp;blinks."&nbsp;The&nbsp;tempting&nbsp;fix&nbsp;is&nbsp;to&nbsp;treat&nbsp;the&nbsp;blinking&nbsp;light,&nbsp;maybe&nbsp;reset&nbsp;the&nbsp;opener&nbsp;and&nbsp;hope.&nbsp;Resetting&nbsp;clears&nbsp;the&nbsp;state.&nbsp;It&nbsp;does&nbsp;not&nbsp;tell&nbsp;you&nbsp;why&nbsp;the&nbsp;state&nbsp;went&nbsp;bad.</p> <p>Nine&nbsp;times&nbsp;out&nbsp;of&nbsp;ten&nbsp;the&nbsp;real&nbsp;cause&nbsp;is&nbsp;a&nbsp;pair&nbsp;of&nbsp;safety&nbsp;sensors&nbsp;near&nbsp;the&nbsp;floor&nbsp;that&nbsp;have&nbsp;drifted&nbsp;out&nbsp;of&nbsp;alignment.&nbsp;The&nbsp;blinking&nbsp;light&nbsp;is&nbsp;not&nbsp;the&nbsp;bug.&nbsp;It&nbsp;is&nbsp;the&nbsp;log&nbsp;message&nbsp;telling&nbsp;you&nbsp;a&nbsp;lower-level&nbsp;check&nbsp;is&nbsp;failing.&nbsp;Reset&nbsp;the&nbsp;opener&nbsp;and&nbsp;the&nbsp;light&nbsp;comes&nbsp;back,&nbsp;because&nbsp;the&nbsp;misaligned&nbsp;sensor&nbsp;is&nbsp;still&nbsp;there.&nbsp;You&nbsp;have&nbsp;restarted&nbsp;the&nbsp;service&nbsp;without&nbsp;fixing&nbsp;the&nbsp;leak.</p> <p>The&nbsp;workflow&nbsp;that&nbsp;actually&nbsp;holds&nbsp;up:</p> <p>1.&nbsp;Reproduce.&nbsp;When&nbsp;does&nbsp;it&nbsp;fail,&nbsp;and&nbsp;what&nbsp;is&nbsp;the&nbsp;exact&nbsp;signal?&nbsp;A&nbsp;blink&nbsp;count&nbsp;is&nbsp;an&nbsp;error&nbsp;code.</p> <p>2.&nbsp;Read&nbsp;the&nbsp;log.&nbsp;The&nbsp;opener&nbsp;is&nbsp;telling&nbsp;you&nbsp;which&nbsp;subsystem&nbsp;tripped.&nbsp;Learn&nbsp;to&nbsp;read&nbsp;it&nbsp;instead&nbsp;of&nbsp;clearing&nbsp;it.</p> <p>3.&nbsp;Find&nbsp;the&nbsp;root&nbsp;cause.&nbsp;Sensor&nbsp;alignment,&nbsp;a&nbsp;broken&nbsp;spring,&nbsp;a&nbsp;frayed&nbsp;cable.&nbsp;Fix&nbsp;that,&nbsp;not&nbsp;the&nbsp;symptom.</p> <p>4.&nbsp;Verify.&nbsp;If&nbsp;it&nbsp;fails&nbsp;again&nbsp;through&nbsp;the&nbsp;thing&nbsp;you&nbsp;"fixed,"&nbsp;you&nbsp;did&nbsp;not&nbsp;fix&nbsp;it.</p> <p>The&nbsp;failure&nbsp;mode&nbsp;I&nbsp;see&nbsp;most&nbsp;is&nbsp;step&nbsp;1&nbsp;and&nbsp;step&nbsp;4&nbsp;skipped,&nbsp;and&nbsp;a&nbsp;lot&nbsp;of&nbsp;resetting&nbsp;in&nbsp;between.&nbsp;That&nbsp;is&nbsp;a&nbsp;system&nbsp;running&nbsp;on&nbsp;restarts.&nbsp;Same&nbsp;lesson&nbsp;whether&nbsp;it&nbsp;is&nbsp;a&nbsp;garage&nbsp;or&nbsp;a&nbsp;service&nbsp;that&nbsp;mysteriously&nbsp;recovers&nbsp;every&nbsp;time&nbsp;you&nbsp;bounce&nbsp;it.</p> <p>Rise&nbsp;Up&nbsp;Garage&nbsp;Doors,&nbsp;Mint&nbsp;Hill&nbsp;NC.&nbsp;riseupgaragedoors.com</p> debugging learning productivity softwareengineering