Volvo Community Forum. The Forums of the Volvo Owners Club

Forum Rules Volvo Owners Club About VOC Volvo Gallery Links Volvo History Volvo Press
Go Back   Volvo Owners Club Forum > "Technical Topics" > 850 / S70 & V70 '96-'99 / C70 '97-'05 General > 850/x70 S1 Articles
Register Members CarsBlogs Help Calendar Mark Forums Read


850/x70 S1 Articles How to's and step by step guides on a specific repair or modification to a Volvo 850/70 car.

  • VOC Members: There is no login facility using your VOC membership number or the details from page 3 of the club magazine. You need to register in the normal way
  • AOL Customers: Make sure you check the 'Remember me' check box otherwise the AOL system may log you out during the session. This is a known issue with AOL.
  • AOL, Yahoo and users. Forum owners such as us are finding that AOL, Yahoo and are blocking a lot of email generated from forums. This may mean your registration activation and other emails will not get to you, or they may appear in your spam mailbox

Thread Informations

Fitting an aftermarket head unit to a Volvo C70 (98 - 03)

Views : 15087

Replies : 0

Users Viewing This Thread :  

Thread Tools Display Modes
Old Oct 2nd, 2009, 21:09   #1
Forum Support Team
1stRaven's Avatar

Last Online: Mar 14th, 2018 14:07
Join Date: Mar 2006
Location: Lincoln
Default Fitting an aftermarket head unit to a Volvo C70 (98 - 03)

Due to various issues with the sc-900/901 found in the C70's, you may wish to upgrade to a new aftermarket head unit. This article will hopefully give you the information required in order to do this. However, if you car has the Dolby surround sound fitted, you will lose the surround effect from the centre speaker as this will become disconnected. Another note is that your new head unit needs to have two sets of fade able pre outs (normally known as front and rears) in order to connect to the amp. A head unit with only front and subwoofer pre outs is NOT suitable.

Before we get started on the adapters, the first thing to do is to take a look at the head unit and cables that connect to it. (See Picture 1 - Rear of the head unit). From right to left, there is the main aerial connection, a secondary aerial, 14 pin square connector, CD changer connector (small din connector), Dolby Surround Cable (larger din connector with about 15 pins), 10 pin square connector, Amp connector (6 pin din connector) and a green centre speaker connector.

The 14 pin square connector provides the following power, electric antenna signal, ground, light dimmer signal and switchable 12v feed in the following format
1 - Nothing connected but would be Left Dash Speaker +
2 - Nothing connected but would be Left Dash Speaker -
3 - Blue&Yellow cable, Antenna
4 - Green&Brown cable, Battery
5 - Nothing connected, can't find out what this WOULD be for
6 - Black cable, Ground
7 - Nothing connected but would be Right Dash Speaker +
8 - Nothing connected but would be Right Dash Speaker -
9 - Nothing connected but would be Telephone Mute (see below).
10 - Pink cable, Rheostat (this allows the illumination to dim)
11 - Nothing connected but would be another ground
12 - Red/Black cable, Battery
13 - Yellow/Violet cable, power when in Accessory mode of the ignition
14 - Black cable, Ground
The 10 pin square connector provides the speed volume connector
1 - Nothing connected but would be Left Rear Speaker -
2 - Nothing connected but would be Left Rear Speaker +
3 - Nothing connected but would be Left Door Speaker -
4 - Nothing connected but would be Left Door Speaker +
5 - Nothing connected but would be Right Rear Speaker -
6 - Nothing connected but would be Right Rear Speaker +
7 - Yellow&Black cable. This is the speed volume control
8 - Nothing connected Don’t' know what this would be for
9 - Nothing connected but would be Right Door Speaker -
10 - Nothing connected but would be Right Door Speaker +
To remove the sc-90X head unit, just press in the two latches on the sides (vertical thin bars) and they will pop out. Use these to grip and slowly pull the head unit out. Now disconnect the cables, making sure you have the radio code and all of the cd’s out of the unit before hand.
Now that we have the old head unit removed, we can fit the two adapter leads. The first one you need is an autoleads cable (Part number PC2-37-4) which will plug into the two square connectors and provide power, ground etc to the new head unit. This then plugs into the ISO inputs on the new head unit so you should be able to power on the new head unit and make sure it all works. However, you will not have any sound at the moment.

In order to get this, you need to either make or purchase a RCA to Din adapter which converts the pre outs on your new head unit into a din input that the Volvo amp can understand (See picture 2). There are various sellers of this cable such as Quickbrick Motorsports or Marcel on the VOC Forum or you can make it yourself if you are handy with a solder iron as the parts are available from Maplins or Ebay for example.

The pinouts for the cable to the amp are:
1 = Front Right
2 = Front Left
3 = Rear Right
4 = Ground
5 = Rear Left
6 = Amp Sense - 12V
To be clear, the pin numbering matches the female connector (radio). Pin 1 is at 2 o'clock, pin numbers increase by going clockwise until pin 5 at 10 o'clock, with pin 6 in the centre.

Once created, you can plug it in and connected the Amp Sense to the amp on/remote amp lead from your new head unit. It is this cable that tells the amp to switch on. Some purchased cables also have a separate ground cable. This can either be grounded separately or into the ISO wiring adapter.

You should now have sound to all of the speakers in the C70. To make sure you have them connected correctly, use the balance and fade options in the head unit to tune the output to each corner of the car at a time.

A couple of side notes
1. Nearly all aftermarket head units do not have a connector for the secondary aerial so you can just leave this disconnected with no ill effects.
2. As stated at the start, your centre speaker will no longer work however there are products out there such as dedicated centre speaker amps which you can use if you so wish in order to power this speaker. You will need a head unit which can output surround sound to do this as well.
3. The Volvo head units seem to have quite a lot of EQ set on them so you may need to spend some time tweaking the EQ if you want to get the sound just right. On mine, I just put the sound slightly forward using the fade option.
4. If you have fitted a single din (half the size of the sc-90X) then Volvo do sell an 8 cd holder and surround in order to fill the gap. The part numbers are 9192749 and 9192751 which cost about 17 - 20 at last purchase.

Credit for the Pin outs and pictures goes to JimmyC
Attached Images
File Type: jpg sc091rear.jpg (21.4 KB, 81 views)
File Type: jpg volvo amp lead.JPG (11.4 KB, 79 views)
File Type: jpg 8cdholder.jpg (24.4 KB, 82 views)
1stRaven is offline  
The Following 14 Users Say Thank You to 1stRaven For This Useful Post:

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT +1. The time now is 08:05.

Powered by vBulletin
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.