I’m a first time home owner and am currently renovating my garage. I went to replace the ceiling light receptacle and the outlet that is connected to it but having trouble making sure it’s correct. I replaced the light with the same that was on it before ( I wished I had changed it because I had these outlets) and I changed the outlet to a GFCI. After installing both and checking with the tester... this is what came up; the light - open neutral, the outlet - open ground. I’m aware the outlet might say that but don’t know if the lights OK. I’m near Chicago if it matters, and the outlet and light look like they are connected to my kitchen outlets and lights. If there’s more info needed let me know, because I really don’t know more info to give right now.
Although Harper is partly correct a GFCI receptacle must be readily accessible and code defines this as 6’7” max exhibit 100.1 in the 2020 code this is also the max height for a disconnecting /circuit breaker switch handle as specified in 404.8.A. The receptacle will need to be moved down or a GFCI circuit breaker installed in the panel to be code compliant.
The problem you currently have is your tester (many on this site refer to them as magic 8 ball testers because you are only sure they are correct when the circuit works other than that it’s a guess).
Have you tried pressing the test and reset buttons on the GFCI many models require this to turn on the first time and some models require it after every power cycle.