Today, you awoke to discover that your iPhone is having a lot of trouble connecting to Wi-Fi networks. What was once an automatic process has now become an annoying problem. Opening your settings app, you see that the Wi-Fi button is now greyed out; you can't reactivate it. Does this scenario sound familiar? If so, we'll outline a fix that may solve your problem. Before we begin, note that we're assuming that the Bluetooth feature is also malfunctioning and won't detect devices as it normally does.
Generally, if your Wi-Fi button is grey and you cannot activate it with a tap, this points to a problem with the hardware on your iPhone--more specifically, the antenna. For many iPhone models, the antenna runs underneath the headphone jack, and even tiny bits of errant debris or moisture can cause a short-circuit effect.
Keep in mind that this issue can affect any model of iPhone including the many versions that do not have headphone jacks, like the iPhone 5, 6, 7, 8, and even the X model. I just mentioned the location above for an easy reference point.
Related: Troubleshoot Why iPhone Won't Connect To Wi-Fi
Using a small flashlight, shine the light directly into the headphone jack of your iPhone. This method does not work on the iPhone 7 or later. You may need to hold it at a slight angle for optimal results. If you notice some debris, use a clean toothbrush (one that is brand new, not just clean, in case you were wondering!) to remove the dirt gently. An anti-static brush will work well in this case, too. On the iPhone 4 models including 4 and 4S, you should see a small white-colored dot at the bottom of the jack.
That dot is what's known as a liquid contact indicator. This indicator is what the techs at Apple use to check whether your phone has come into contact with any liquid. If you see that the dot is red instead of white, it's almost certain that your iPhone was exposed to liquid at some point.
This provides one explanation but we can't rule out the issue being a software problem. Before we do that, let's try resetting your iPhone's Network Settings first. Go to the Settings tab, then within Settings the General tab, and from there navigate to Reset, and finally, press "Reset Network Settings."
Be sure to have your various Wi-Fi passwords handy for this part though; this action will erase those passwords from your iPhone. Head to the Wi-Fi section of your Settings after the phone reboots itself to input the passwords and get everything up and running again.
If the problem still persists after the network reset, it's a confirmation that the issue is one of hardware. Since Apple techs will not repair only the antenna on an iPhone, you'll have to get a replacement phone. I'd recommend going through Apple directly provided your phone is still under warranty. This is precisely the kind of issue from which the warranty protects you.
If your warranty has expired, my recommendation would be to get the new phone via AppleCare or the Genius Bar; both options allow you to get a new phone at far below market cost. It's still not going to be inexpensive, but it's the best you'll get. You can visit apple support online or place a call to the Genius Bar to get the ball rolling.
If you're really attached to your current iPhone, there are a couple avenues you can try instead of a whole replacement. The company Puls will send a tech to you who will fix the iPhone, possibly for a better rate than the Apple Store. Even better, they're happy to visit you at home or the office.
If you are confident in your do-it-yourself abilities, iFixit offers detailed repair instructions for most everything Apple. It's here you'll find some interesting fixes that may potentially solve your antenna problem, like placing the iPhone in the fridge for a while.
Lastly, if the DIY repairs aren't working, iFixit provides guides for replacing the antenna yourself, too. Note that this is mostly for very advanced, tech-savvy users who have preferably already performed iPhone repairs in the past.
