PSA: Stop replacing glow plugs on cold starts without checking this first

I see too many guys throw new glow plugs at a hard start and call it fixed. Most times, the issue is with the relay or wiring harness corrosion. Grab a test light and check for power at the plug connector before you tear anything apart. On a 6.7 Powerstroke last week, a bad ground connection mimicked a dead plug. Cleaning the terminal fixed it in ten minutes, saving the customer a full set of plugs. Always verify the simple stuff before assuming the part is bad. It saves time, money, and stops comebacks.