I have a 1999 Subaru legacy 30th anniversary edition with the factory sub. it has the p117 radio with it, i was replacing the radio with a p121 which ive done on other legacy's before, I unplugged the old radio because it did not have working cd player, i put the p121 which worked great from a 2001 legacy and it did nothing, i put the factory radio back in and it does nothing, the security light does not blink anymore and does not honk when i lock the doors like it used to. I do not have the fob, also I dont need the security system I just want to listen to music. ive checked all the fuses and i had blown some of the radio fuses on the kick panel, replaced those still nothing, at night when i turn the lights on the factory radio i left hooked up lights up, the back lights and button but does nothing.

I just put a ej22 in this Subaru and im 16 and just need help on getting started where to look, I tried to find factory diagrams but there for the models with a factory sub and its different with the wiring routing and coloring, anyway sorry for the talk fest but im just having difficulty's on what to do im not good at electrical

I haven't really done any stereo swapping (other than just trying to make sure each of my cars has a factory AM/FM/CD) and don't care about subs, so I can't help on that front - I don't even know what the P117 and P121 models are.

But as far as the (Alpine) security system goes, you can just unplug that module and the keyless entry will still work (when you get a fob), as it's a separate module.  So that will at least remove the security system misbehaving as a variable.

39 minutes ago, jonathan909 said:

I haven't really done any stereo swapping (other than just trying to make sure each of my cars has a factory AM/FM/CD) and don't care about subs, so I can't help on that front - I don't even know what the P117 and P121 models are.

But as far as the (Alpine) security system goes, you can just unplug that module and the keyless entry will still work (when you get a fob), as it's a separate module.  So that will at least remove the security system misbehaving as a variable.

P 117 and p122 are both subaru radios i cant find anything like that on my car, nor did i have to splice anything they both have the same radio plugs.

have you tried here for wiring diagrams? http://jdmfsm.info/Auto/Japan/Subaru/

 

The ground from the radio harness is critical!  

Make sure the ground wire going to the frame from the radio bracket is hooked up.