The $22 fix for my Silverado's AC that the dealer wanted $700 for

My truck's AC started blowing hot air back in June, and the dealership in Fort Worth quoted me $700 to replace the whole compressor. Before I paid that, I did some digging online and found out it might just be the AC relay, a tiny $22 part under the hood. I swapped it out in about five minutes in my driveway and cold air came back instantly. Here's the funny part though, and this ties right into the warranty stuff. My extended warranty covers the compressor but not that little relay, so if the dealer had gone with their plan I'd have been on the hook for a $700 job that insurance barely touches. It made me read my contract line by line for the first time and I noticed a bunch of cheap parts like sensors and fuses aren't covered at all. Now I check the small stuff first before filing any claim. Has anyone else gone through their coverage and found these little gaps that cost you more than the big stuff?