99 s70 T5 Radio issue

blandis · Post by **blandis** » 20 Apr 2012, 17:34

Had my dash repaired by a local mechanic. Radio worked fine when the car went in and now only the center dash (dolby) speaker works. Took it back and all connections look fine, no cut wires ect. We pulled the front seat, unplugged the amp and checked all connections.

Made a guess that it is the HU. Ordered a new Kenwood from crutchfield, installed it and only the two dash outer speakers work with it hooked up.

Thought I would post here before dropping it off at a stereo shop to trouble shoot.

Post by **jimmy57** » 20 Apr 2012, 20:28

IS the Kenwood using the factory amp or is the amp bypassed and Kenwood runs speakers via internal amp?

Post by **BEJinFbk** » 20 Apr 2012, 22:01

That's the outboard amp not working for some reason or another. It runs the 4 corners
If the wrencher that pulled your dash doesn't know how Volvo premium sound amps
are installed, it would be easy to connec the wrong thing in the wrong place.
It's a big job and the amplified audio cabling shares some common connectors.

I'll bet the amp bypass cable was plugged together incorrectly.
Here's a rambling and somewhat confused post on the subject...
( At least my part of it. Post with any questions.)
https://www.matthewsvolvosite.com/forums ... =1&t=30204
Reading through this will hopefully get you pointed the right direction.

It's a bummer you didn't post before you put in the Kenwood. This woulda been waaay easier.
I don't know how you installed the Kenwood, but I can help you with how the the stock
setup should have been connected. It may be confusing, but I hope it helps.

The easiest way to tell if the wrong connector made it to the back of the radio is to look.
The smaller of the 2 main connectors ("B") at the back of your stock HU would only have 1 wire.
That means that the back of your stock HU would have look something like this:

: SC-901 rear - while connected sm.jpg (35.47 KiB) Viewed 3306 times

If the smaller black rectangular connector on the right is chock fulla wire,
and you're using the OEM Volvo amp RCA to DIN adapter cable that's the problem.

I'd be sure that anyone you may take it to understands
how Volvo stereos are wired through the optional amp.
Nail that down upfront. Don't let'em chop up your car!

blandis · Post by **blandis** » 22 Apr 2012, 07:49

Kenwood was from crutchfield. Used their wiring harness, so no wires or splices to the factory wires/harnesses. Have seen those rats nest before.

I have the factory radio back in, same issue. Only the center (dolby) speaker works on a few settings (3 ch, have hit mode button). You put it in regular stereo mode an you get no sound at all.

Put the kenwood in and only outside front dash speakers work. assume they are just tweeters, as they sound like it.

I have factory stereo back in. Pulled the seat and carpet for the dash/console footwell area, have visually inspected all the harnesses and wires. Again, visually it all looks fine.

Looked on ebay for a amp, could not find one. I would like to try that before attempting to bypass the amp. My preference would be to do away with the factory unit, and us the kenwood so that I can use pandora and my iphone.

Thanks in advance for your help.

Post by **BEJinFbk** » 22 Apr 2012, 11:19

Time for pics.
Can you show us the harness connections?

blandis · Post by **blandis** » 04 May 2012, 22:01

BEJ
I have the seat out, cant find any wires cut or pins unplugged from any of the plugs. Any way to just bypass the amp?

I would prefer to just install the kenwood and run the speakers off that if I can? Done messing with the factory system, and not sure I want to throw parts at it. Tried to find a used amp on tow forums and ebay. No luck.

Guess Im ready to call uncle and surrender to the factory radio gods.

velorossa · Post by **velorossa** » 05 May 2012, 00:19

I have a 98 V70XC that I'm parting out. I don't know if there stereo and amp are the same as you 99 but I would imagine they are the same.

Post by **BEJinFbk** » 05 May 2012, 01:22

Was the mechanic under the seat? If not, it isn't surprising that everything there is OK.
You never posted any pics. Shoot us some pics of the connectors where the HU plugs in.

And yes. Bypassing the external amp is very doable. But I'll bet yours is fine.
This all started when someone unplugged a bunch of stuff in your dash, right?
I'm 99% sure that they just got it all plugged back together wrong.

The optional external amp harness intercepts the two big plugs that usually
go into the back of a stock HU ( Like an SC-816 ) that has a built in amp.
It runs all those wires from the car side plug and the HU back and forth to
the external amp, except the amplified HU's speaker outputs. That signal
runs on the round 6 pin "AMP" DIN cable. ( The amp turn on is in the DIN, too.)

The amp does it's thing with the HU's preamp level signals from the 6 pin DIN cable and
sends the amplified speaker outputs back up the cable to a connector that's identical
to the one on the back of the HU. The car side plug goes there. Since the harness uses
a duplicate set of the 2 main connectors, car side and HU side, they're easy to mix up.
( Sure, it makes it a simple plug and play upgrade for a dealer, but easy to mix up. )

This is a picture of the underseat amp and it's bypass harness:

: Volvo OEM 4 x 50w Amplifier for 850 S70 V70 and wiring harness 9452029 - 9452030 marked up.jpg (71.6 KiB) Viewed 3230 times

And a "roadmap":

: Volvo OEM 200 Watt 4 Channel Amplifier flowchart for 850 S70 V70 and wiring harness 9452029.jpg (75.5 KiB) Viewed 3230 times

Again, post some pics of your connections, please.

blandis · Post by **blandis** » 05 May 2012, 10:43

BeJ,

you nailed it. That was the issue, had a harness plugged in the wrong way.

There are two plugs exactly the same, one bungle has a "R" on it and goes to the back of the radio. It was plugged in to a different plug.

Wow, what a PITA.... truly appreciate your help! I owe you one! The pics really got me headed in the right direction.

Post by **BEJinFbk** » 05 May 2012, 12:40

Glad you got it.

Music on the road is important!