Relay found but not sure what it is fo

I just had my car broken into and sombody stole the aftermarket headunit in my car. Luckily nothing else. I had them installed by a professional, because i dont know much, well they took everything with the headunit including the harness and cut my monster cable rca's.    I found relay in there, which the remote wire from the amp, is connected to the 30amp stub on the relay. what was the purpose of the relay? would anyone know? why would he install the remote wire from the amp to a relay instead of going directly to the headunit? i do have a power antenna, not sure if they would play a role in it?

Well since the turn on lead was leading to 2 things the installer may have put the relay in to bump up the amount of devices that it connect to. There is nothing wrong with it, in fact this would be the "correct" thing to do. Maybe overkill for 2 devices but still correct.Certified Security Specialist

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Ok, great i would like to install a new aftermarket head unit, and connect the relay like it was originally, what else do i connect to the relay from my harness? thanks!!!

yea it would be great.

I know why now, I believe the reason for the relay wired up to the remote, could be because the original aftermarket wire harness for my car was the old model style , with 13 pins, where the newer ones that they make now consist of 14. the old 13 pin adapter harness does not have the blue/white = remote turn on wire. it only has a blue wire harness for the power antenna. Because of this type of wire hanress, the installer must have used the relay, to trigger the power antenna, and the remote turn on 12v+ for the amp, when the headunit was turned on. I'm not to sure. I am still trying to figure how he had it wired up. to the relay... the relay has 5 pins i blieve.... hmm.. Well anyways, the newer 14 pin adapter harness's has the blue power antenna + the blue/white= remote turn on 12v+. so any ideas if my theory is correct?

the only reason u would need both the blue and the blue white is if the car has a factory amp.....the reason the installer had the relay was to supply a suffecient amount of current to the amps in the back.....what type of car is it?  also u only will use 4 of the pins on the relayWhere theres is a wire there's a way.

u would use 85 (ground) 86 (remote turn-on from head unit) 87a (not used) 87 (12+ constant) 30 to amps and remote turn in car aftermarket harness.Where theres is a wire there's a way.

You rock! I'll keep you updated on how things go.

I just wired up my headunit using the relay. i noticed when i took the remote wire from the headunit and touched the blue antenna wire from the car, it powers the antenna, but then when i took the same blue antenna wire and connected it to the amp remote turn on it does not power up the amp. whats going on?