Replacing HU-555 with aftermarket head unit
 

Hi

I have a 2004 V40, and I replaced original HU-555 stereo with a new one. There is the original subwoofer in the trunk but after stereo swap it's not working. I assume it takes audio signal from other speakers wiring, as there was no DIN cables connected to the head unit.

I bought a kit that changes original wiring to standard ISO connection. But what wires I need to connect to the head unit to power the subwoofer amp? Rear speakers, front door speakers and dash tweeters are powered by the head unit.

I tried to google it but couldn't figure it out yet.

Here is an image of the connector

HU 555 https://imgur.com/gallery/dTigza2

Thanks in advance!:regular_smile:

There are 2 systems fitted in these cars that include the sub, one is the more basic setup where just the sub is powered by the inbuilt amp, and all the other speakers are powered by the connectors in the grey plug, and then there's the premium system, where the door speakers, rear speakers and the sub are amp powered, so only the dash tweeters are powered by the aforementioned connector, I discovered the 2nd system when fitting my aftermarket unit into my old SE while the T4 was busy having a broken engine, all I had was tweeters.

however, so far as I understand it, in both cases to get a signal to the amp there is a din connector, as that's what drives the amp, for that to work it will indeed need to be powered, the 12v blue remote wire on aftermarket units being the perfect thing.

you'll need to have at least one set of sub / amp RCA pre outs on your new stereo for the signal though, ideally 2, but if it only has one set you can always use splitters, the main part you'll need is the din to RCA powered adapter, which is autoleads pc9-414, that's what I used in my old 52 plate SE which had the later system, the sub was broken in my 02 T4 that has the earlier system so i never bothered with it, i hope this helps.

There was no DIN connected to HU-555, so I think subwoofers amp takes signal from speaker wires.

https://www.matthewsvolvosite.com/fo...ic.php?t=30204

Here on another forum someone suggested that the red-and-black is the remote wire color for subwoofer.

Would it be a bad idea to just try connect the blue remote wire from the new head unit to Volvo's original connectors red and blue wire? I mean after all there is fuses everywhere... :rolleyes: :rolleyes:

Never mind, already found the wiring diagram :) thanks anyway

Ahh ok, apologies, I was just going on what was the case in mine with the hu605, and also what i read here before.

https://www.volvov40club.com/threads...-stereo.23170/