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 FAQ #199
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Can I Fit an after market Head Unit to a C4 and what do I need?
So you want to add an aftermarket head unit, but don't know where to start?

As this crops up so often, I thought I might as well just do a small guide.

Few things first, depending on specification of the car you will be looking at between £60 and £120+ for adaptors alone. This is before you even take the head unit price into consideration. That is to keep full functionality of steering control functions. Volume, pause, skip tracks etc. Higher the specification of the car the more it is going to cost basically.

If you have the standard CD Changer, unfortunately it will stop working with an after market unit. Even if you fit a Blaupunkt unit.

The usual adaptors are listed below. Using purely Connects2 adaptors as they are the ones I have experience with. Others are available but do not use Autoleads ones from the likes of Halfords as they are known to cause problems, especially battery drain.

Click the red arrow to take you to the products web page. Part numbers / Part reference in Blue

Patch leads for steering controls, MUST BE CONNECTS2 PARTS - £4 - £6

Kenwood Head units - CTKENWOODLEAD - Click Here -

Pioneer Head units - CTPIONEERLEAD - Click Here -

Alpine Head units - CTALPINELEAD - Click Here -

JVC Head units - CTJVCLEAD - Click Here -

Sony Head units - CTSONYLEAD - Click Here -

Panasonic Head units - CTPANASONICLEAD - Click Here -

Clarion Head units - CTCLARIONLEAD - Click Here -

Beat Head units - CTBEATLEAD - Click Here -

Blaupunkt Head units - CTBLAUPUNKTLEAD - Click Here -

Reverse Sensor Interface Connects2 CTRCT001 .... Will not work on most 2006 and earlier builds. 2007 and onwards should work perfectly. - £40 - Click Here -

Aerial Adaptors

Usually around £15 - £30.

Again this changes depending on head unit fitted and if the car has twin aerials. Usually, twin aerials are only found on Exclusive / VTS trim levels. However, not all are equipped with twin aerials. Those that are, don't always have them both wired up either.

Would provide links for these but there would be around 8 different aerial adaptors, which could confuse things. Check your head unit and see what connection it requires. Then check the aerial in your car and work it out from there. Just make sure it is amplified.

They will usually be active (amplified / boosted) Single Fakra to DIN or Fakra to ISO
Some will use active (amplified / boosted) Dual Fakra to DIN or ISO. If you have a twin aerial car.

You really have to physically check to find out which you will need.

Fitment issues

Be warned in Coupe's and Hatches there can be a slight lip, where you will be able to see the top of the Air Conditioning unit due to the fitment. Won't look quite as tidy. Again some head units are worse than others for this. Depends how much they stick out. This does not affect the functionality, purely the aesthetics.

You can purchase small spacers from places like Halfords, that will allow you to get rid of the majority of the gap should you wish. Usually around £10+


This also crops up quite often when people are looking at doing an overall upgrade.

The speakers in the C4 are 17cm or 6.5" front and rear. Fronts are easy to install rears can be more difficult. Always best to upgrade front speakers first though. Don't just go and add big rear speakers. On the parcel shelf. You might think it seems logical as they are further away to upgrade those first. However, all that will do is reduce sound quality and drag the sound stage further back. Upgrade the front speakers first. Someone once told me a great way of thinking about it, with a little question. "Would you go to a concert and sit with your back to the stage??"

So don't do effectively the same thing in your car, by upgrading the rear speakers and leaving the fronts standard. Your ears are positioned to best hear things in front of you. Keep that in mind.

Obviously if you have lots of passengers in the rear. Then it might be a good idea to upgrade those as well. However I would personally say just stick to the standard 17cm coaxial speakers.
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FAQ Posted by wozza
Info Created: 13 May 2010
Last Updated: 04 September 2014