Chosen Solution
So I opened up my Mac to clean out dust and replace the thermal paste. Put everything back together but it won’t connect to my other monitor. “No Signal”. Is there something wrong with the HDMI? I don’t think I touched anything that would have affected that, it was working fine like 5 minutes before I shut it down to open it up.
Sounds like you forgot to connect the I/O board or the connection is not firm or the connection is damaged (cable or board connector) MacBook Pro 13" Retina (Late 2013-Early 2015) I/O Board Data Cable MacBook Pro 13" Retina Display Late 2013 I/O Board Replacement
