iPhone 7 incredibly weak WiFi and Bluetooth

[iJTL]

Hi guys!

 

Got a bit of a problem here. I recently bought a used iPhone 7 off of Facebook. The phone works great, everything works great; all the buttons, 3D Touch, microphone, speakers, mobile data, everything except two things - WiFi and Bluetooth.

I have an unlimited data plan, so I didn't notice this right away, but the WiFi signal seems to be incredibly weak, when I'm standing next to the router, I have only 2 bars (out of 3), if I'm even a few feet away it drops to one and won't even connect (comes up as incorrect password, even tough I'm 100% sure it's correct).

Bluetooth is also unusable. My Bluetooth headphones kept cutting out when my phone was in my pocket, with any other phone they only start cutting out when between me and the phone are several walls.

 

Here's what I've already tried: 

• Hard resetting (factory reset)
• Resetting all network settings
• Re-pairing my headphones
• Turning it off and on again (soft reset)

 

The previous owner said he had the battery changed a couple months ago, but to my understanding, it was done by a repair shop (not DIY or Apple themselves), is it possible the repair shop guy could've nicked some antenna/flex cable?

 

The previous owner also worked a manufacturing job, so the phone's body is pretty scrapped up by debris stuck inbetween the phone and the hard plastic case he used. Could this be caused by damage to the antenna bands visible on the outside of the phone?

 

All of my findings on Google suggested the software stuff I already did before Googling and if those fail, going to an Apple Store, but that isn't an option for me, as the nearest one is in a different country and is 400km away.

 

Has anyone else experienced this or a similar problem before? If so, how did you fix it? What part appears to be faulty? From my understanding, the iPhone has two separate WiFi antennas,  short range and a long range one, and a separate Bluetooth antenna. If it comes down to just replacing a faulty part, I'm confident in doing that myself, as I've replaced iPhone parts before.

 

Cheers!

[DrMacintosh]

It is possible that the battery replacement did cause issues or that an antenna was not seated properly. You're options are to open the phone and check for yourself, take it to an Apple store and get a diagnosis, or contact Apple support and ship the phone to them.