Big issues with head unit, car alarm, central locking, please help!

Hi guys,

Pulled my head unit out of the hole in my dash last night to quickly chuck a aux in cable in, I couldn't quite get to it so I disconnected the headunits's socket for the wiring harness and plugged it in, went to plug it back in and no security light flashing, turned the car on. No life, I checked the head units' fuse, and its intact and so is the 'stereo' one under the steering wheel, I gave up on fixing it so came back 30mins later and my mongoose m20 alarm when disarmed started flashing faster (light inside car, it should stop flashing) and then when i closed the door the alarm went off, Now the remote doesn't lock the doors when i arm it, and if I don't turn the engine on in 30 secs of un-arming, the alarm goes off, and now when I lock/unlock the car with the key it only does my drivers door (before the alarm it would lock/unlock all doors) any ideas? I'm baffled! Btw I have a 2002 ep3 civic

Tried disconnecting battery/resetting ECU? I usually just try it whenever random electrical crap is happening.

You could try the above, otherwise...

Sounds like there may be a short somewhere since plugging that AUX in?

I suggest try doing everything you did in reverse order to try diagnose the problem.

It wouldn't be plugging that AUX in be the problem, perhaps it was the process taken up to the point of when you plugged that AUX cable in.

Check if the earthing has not loosened or some other major wire; check if there are any exposed wires in contact with other metal bits behind the HU.

If you could probably take pictures and post up here the HU area in discussion perhaps everyone could see for ourselves what the problem could be since it is hard to picture. :)

Good Luck.

I already have tried disconnecting the battery, idk what else to do

is your headunit and immobiliser connected ?