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98' S70 Amp Help-mystery wire and mystery white box in trunk, no amp found

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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98' S70 Amp Help-mystery wire and mystery white box in trunk, no amp found

Post by S7turbo »

While trying to find the amp in my car (that turns out to not be found ) , I have found two unattached cables in my trunk, and a mystery white box....what are these? These are on the driver's side, and hidden behind the carpet by the antenna.
the two cables just sitting there
the two cables just sitting there
The mystery wire of the 2 wires is the one that has the rectangle-ish connector. It looks like the same lighting connector for a light, but is in an odd location. It's connector looks like the same one for the trunk light, and also the same connector for the left and right knee-level courtesy lights that go on when you open the door.

The other round cable appears to be the other end of the amp cable from the front of the car but it doesnt appear that anything was connected to it before, just wires sitting there. I looked everywhere for a factory amp, but this is all I found. It wasnt behind the stereo, nor under the passenger seat. With this unconnected amp cable in the trunk, can't I just pick up a similar year volvo amp at a wrecking yard and plug it in?
closeups of cables
closeups of cables
The factory stereo went out, so I installed a Kenwood head unit and now I'm trying to improve the sound and the amp would have been nice to use....
this is cable up front
amp cable behind stereo
amp cable behind stereo
this was in car, no longer works
this was in car, no longer works

And the unknown white box not that far away, I have no idea what this is or if even related.
unknown white box
unknown white box
Thanks everyone!
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Re: 98' S70 Amp Help-mystery wire and mystery white box in trunk, no amp found

Post by 101 »

The amp for the S70 was only ever mounted behind the radio on the tunnel or under the seat. I thought the T-5's came standard with an amp, but maybe not.

I believe what you have in your trunk is for the accessory 6 CD changer - its data cable and its power connector. These were pre-run from the factory. And I believe the white box is a radio signal amplifier for the rear mounted antenna.

Others may know better. I have a wagon.

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Re: 98' S70 Amp Help-mystery wire and mystery white box in trunk, no amp found

Post by rspi »

I have never seen an amp in any of the x70 cars (except the C & R's). The few that I have seen in the 850's were in deed behind / below the radio.

The wire is for a CD changer. Few were pre-wired.

The relay you see, white, is the rear/tail light controller.
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Re: 98' S70 Amp Help-mystery wire and mystery white box in trunk, no amp found

Post by scot850 »

I have pulled amps from many S/V70's and not all were 'R' or 'C' versions. It depends on which radio head you have fitted. Your radio does have the connector for the amp, but it may not actually have one fitted. As Robert correctly advised they are either fitted directly behind your radio (98 and older typically) or under the passenger seat under the inner seat rail.

If you want to add an amp, make sure you get the additional cable to loop in the amp for the amp under the seat. Can't advise on the other version as I have never seen one!

The SC-900/901 head units with the built in 3 CD changer do not have a pre-amp built into the head, and so require the external amp.

The white box is also as said, the antenna booster, some are part of the mast assembly.

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Re: 98' S70 Amp Help-mystery wire and mystery white box in trunk, no amp found

Post by Ozark Lee »

The unknown white box is actually the bulb failure monitor for the rear lamps. Most of them that I have seen are a blue box but I have also seen them gray colored. It doesn't control the lamps but it does monitor them and trips the light bulb warning light on the instrument cluster when a lamp burns out.

The other cable is indeed for the optional CD changer that was usually trunk mounted on a sedan.

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