HU-803 stereo replacement help?

Redbox · Post by **Redbox** » 19 May 2017, 21:02

So, I have the HU-803 in my v70r, and want to replace it with a new Pioneer AVH-X490BS. I ordered the standard Volvo wiring harness, new face plate for the dash and the antenna adapter. The wire harness I got has two rectangular plugs, but when I pulled the stock stereo I find one rectangular plug and two DIN plugs, so the new harness won't work. I understand there is an amp under the seat, and I guess some of the speakers are fed from that. I want to keep and use as many of the factory speakers as possible. I've searched for days trying to figure this out, and hoped that someone might be able to point me in the right direction for info. Wiring diagrams, adapters, etc. Any help would be greatly appreciated.

Post by **JRL** » 19 May 2017, 21:26

The correct harness should be available
Yes, speaker wires go off the underseat amp
Where did you find the right faceplate? Hasn't been made for a very long time in the correct dark grey ( a one year cover plate, 2004)

Post by **kranz** » 20 May 2017, 03:06

I don't recall where I found this diagram (my apologies to the original poster).

Post by **oragex** » 20 May 2017, 06:39

kranz wrote: ↑20 May 2017, 03:06 I don't recall where I found this diagram (my apologies to the original poster).

from here

http://www.tehnomagazin.com/Auto-radio- ... nector.htm

The amp powers all but the center (dash) speaker which is wired directly to the head unit CT+ and CT- slots. Remember that the center speaker only works on Dolby and 3CH settings, while on Dolby the rear speakers don't have output.

Post by **JRL** » 20 May 2017, 09:10

He's adding aftermarket, he will lose the center speaker

Post by **erikv11** » 20 May 2017, 11:41

oragex wrote: ↑20 May 2017, 06:39 ... The amp powers all but the center (dash) speaker which is wired directly to the head unit CT+ and CT- slots. Remember that the center speaker only works on Dolby and 3CH settings, while on Dolby the rear speakers don't have output.

Apologies to OP for the thread jack but this is relevant: So if none of the speakers is making sound in a HU-803 setup, like the problem is the HU and not the amp, correct?

Post by **oragex** » 20 May 2017, 12:06

If the center speaker is properly connected (assuming it was an original equipment installed on the car and not some upgrade like I did on mine), it should work on Dolby mode even if the amp is busted. Just make sure to play with the Centre Effect knob, pull it in both positions and turn it left and right, when checking if the CS works. A busted amp will usually show signs of corrosion on the metal housing.

I'm actually not sure the CS works in 3Ch mode, JRL can help you with this. I bridged my CS so it works in all modes which is not the standard/original connection.

Redbox · Post by **Redbox** » 22 May 2017, 17:26

Thanks for the feedback everyone. I think I found the final part of the puzzle, but have to wait for delivery. When/if I get it worked out, I'll report back here with info on parts, etc.

Peterdb · Post by **Peterdb** » 30 Sep 2018, 01:28

good morning you all,
Got also the same problems as no sound at all.
Every thing else is working perfectly but no sound getting out of it.
Been in contact with the supplier but also there is now a no-go anymore, even he don't know and send me to this site, so sorry if I jump in here.
But we all drive a Volvo and joyful like to drive this fantastic car.
I will place some pics here to make it all more clear.
quote:
I did all what was needed to have the sound cables connected.
Have a small blue colored cable but I presume this is the ground as the round stick is no w not connected to the unit (as original Volvo), all other cables connected but still nothing.
Have you got any further trick what to do to have sound in the unit?
unquote
quote:
Hi Peter, are you saying that this blue/white cable is not used at this moment? It is the remote turn on wire for factory amplifier. If it is not connected, then the amplifier does not turn on at all and cause no sound.
Please connect this wire to the red wire from our unit's harness to get +12 V power.
unquote.
So far the communication with supplier that actually a good man that try to help me, must say that.
Have done all what was needed but now still not having sound.
I read here that the Amp is under my seat??? Can somebody explain that to me as I never saw an Amp under my seat.
Anybody that can give me a hint what to do is highly appreciated.
Pics show the new after market sat nav and the wire system on back side of it. You can see there that I connected the red with the blue cable on the suppliers request but still nothing.
Waiting yours,
Have a nice day,
Peter den Breejen.

Peterdb · Post by **Peterdb** » 02 Oct 2018, 00:38

Problem solved!
I did give it a last try yesterday and used NOT the combination thin red-blue but YELLOW-thin blue and voila, it works all!!
So even if you buy an aftermarket Sat Nav from China without any further instructions it still can get it to work!
Now having sound on my radio, CD, mobile and sat nav., even can change the language between nearly all in this world but took English. So if anyone has the same problem as me let me know as now I know where to look for. Must say that NO wheel controls are working like changing radio stations, changing CD, but I don't mind.
Anyway, this topic can be closed as all solved, thanks.