My AC is Causing My Electrical System Turn On/Off aka Short Out

So it has been super rainy here in South Texas, like monsoon weather. I say this because I don’t know if it’s the reason I have suddenly started having issues with my car. About a week ago my car started doing this thing where when I first start it up and am idling (usually I have to drive a block or so for it to happen) at a light or stop sign, the electrical system will start flickering. Meaning the lights, entire dash, radio and air conditioning will rapidly turn on and off. My car will stay going but I have no electrical systems. This happened maybe once every other day and now it’s happening every time. I took it into the mechanic and he noticed that if I turn off the AC then it’s idling fine and no electrical outages are happening. He checked the alternator and battery and they are fine. I had to have my car jumped to take it in to him because it wasn’t starting up and making the clicking sound. He says all that is fine so no idea why that happened. He ran diagnostics and the O2 Sensors were having issues. This is an expensive part (like $300 for one of them) so we did a tune up and he replaced the spark plugs and air filter. I hadn’t done this maintenance in forever and am off by about 20k miles on that maintenance. Hopefully that will help that system work better. But the AC is still making the electrical system wonky. If I am driving down the road with the AC it’s fine, it’s only idling.

Any ideas?

Oh, my cruise control light is also burned out but the cruise control works fine. Could it be a fuse?

I have a 2005 Honda Civic EX.

Thanks! <3

Bad grounds can cause this. Dirty battery terminals too. The ground between engine and firewall or fender may be rusted or missing. Easy to improve that one.

Cleaning the main ground from the battery to the chassis along with the battery connections is a good first attempt for the fix though my real suspect for this problem is the ACC contacts of the ignition switch. Check the voltage getting to the dash fuses for those things you mentioned, like the radio, while the problem is occurring.

The O2 sensors have no relation to the trouble you mentioned. If they have an issue also then you should get that fixed as that will effect your engine performance.