The icon showing active Wifi is remaining gray
Welcome to the forum.
What device? What version of the OS for that device? How do you know you have a connection, if the WiFi fan is greyed out? We need a lot more information before we can begin to tackle this issue with you.
It seems the network connection is not sticking.
Ding, ding, ding, we have a winner! The fan is for WiFi, but being directly wired to the router means the Ethernet interface is active and providing connectivity. The fan being there or not is immaterial if you are wired to the router. But the symptoms of fading in and out, when other devices don't see that same problem may mean that the Wifi components in the iMac are failing. On my MBP I am both wired into Ethernet and using WiFi. I run that way so my Watch can unlock the MBP for me when I tap the space bar to wake up the Mac. But the fan never changes, staying at the same strength. If it's really important to you (and if you are wired to the router, it may not be a big deal), you can take the iMac to an Apple store to have them diagnose it. But any repair to a 7 year old iMac may not be be worth it.The computer is directly wired to the router
Thanks to all for the reply. Yes, I'm directly wired from router to iMac. But still, the problem of the gray fan intermittent is new. For years the fan was black, now it goes gray sometimes as discussed.
Generally speaking, the computer with the installed (last year) Sierra 10.12.6 seems to be occasionally freezing. Slowing down. Being inconsistent. Is this Apple's way of saying "time to buy a new, faster machine"?
Patrick, turning on the Wifi cost me essentially zero. I got the watch for other reasons, the auto login is just gravy.
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You need to move into the 21st century! ;D