The Clio 3 is a 2009 car with a 2009 dashboard: a radio with no Bluetooth, no DAB, and no line-out for a sub, and a small info display sitting above it that shows the time and little else. Both were worth replacing, and they do different jobs, so they ended up as two separate installs.

The head unit handles sound. The tablet handles everything you look at. Here is both.

The head unit: sound#

Pioneer MVH-S520DAB-AN. 1-DIN, mechless, so there is no disc drive eating the depth behind the fascia and the wiring has room. DAB+, Bluetooth, USB, AUX. The part that decides everything downstream: three RCA pre-outs (front, rear, sub), MOSFET 4x50W, 13-band EQ, time alignment.

The pre-outs are the reason for this unit over a cheaper one. A sub with no line-level input is a wiring mess. Three clean pre-outs means the amp and the active sub (a Pioneer TS-WX140DA under a seat) get a proper signal, and the EQ and time alignment live in the head unit where I can actually reach them.

Fascia: ACV 281250-03, the 1-DIN Radioblende for the Clio III (2005-2014). It turns the Renault double-height opening into a clean 1-DIN slot with a pocket underneath.

The connector question#

Renault did not run one radio connector across the whole Clio 3 production. Yours is one of two, and which one you have decides the wiring job:

Factory radio connector?
   |
   +-- already ISO            -->  Pioneer ISO loom plugs straight in
   |                               + Fakra->DIN antenna adapter
   |
   +-- Renault Quadlock/20-pin -->  Renault Quadlock->ISO adapter loom
                                    -> two ISO plugs (power + speakers)
                                    -> Pioneer loom plugs into those
                                    + Fakra->DIN antenna adapter

If the factory radio already terminates in ISO plugs, the Pioneer loom plugs straight in and power and speakers are done. If it is a Renault Quadlock or 20-pin, you need a Renault Quadlock->ISO adapter loom (Connects2, ACV, or a generic "Quadlock ISO adapter for Renault"). That splits the single Renault connector into the two standard ISO plugs, power on one and speakers on the other, and the Pioneer loom plugs into those.

The antenna is a separate problem either way. Renault uses a Fakra plug, the Pioneer wants a standard DIN. A Bingfu Fakra->DIN adapter bridges it.

NeedPart
Head unitPioneer MVH-S520DAB-AN
FasciaACV 281250-03 (Clio III)
Power + speakers (if Quadlock)Renault Quadlock->ISO adapter loom
AntennaBingfu Fakra->DIN

The Renault-specific trap#

The adapter loom has to be Renault-specific. An ISO adapter built for a VAG car has the same plugs and a different pinout, so it fits and does not work. The Audioproject A124 is the one to avoid here: it is a VAG harness, it physically mates, and it is not plug-and-play in the Clio. Order the loom that says Renault, not the one that says universal.

The tablet: navigation and the dashboard#

The upper display slot - the little screen above the radio - came out, and a third-party Android tablet went in its place. It is not an audio device and it never touches the speakers. Its whole job is to be the glass: turn-by-turn navigation, and the live dashboard from the OBD Pi.

The tablet is rooted and runs microG instead of Google Play services. Two reasons.

No Google in the car. I do not want a Google-tracked device wired into the dash, awake whenever the ignition is on, logging every drive. Same reason the rest of my stuff is degoogled. microG fills in the Google APIs a maps app expects, so navigation works without the surveillance layer underneath it.

Root makes it an appliance, not a phone. With root I can lock it down to behave like a fixed dashboard: boot straight into the display, no lock screen, no notifications, no Play Store nagging, restricted to the apps I put on it. A stock tablet fights you on every one of those.

What it shows:

  • Navigation - a maps app for turn-by-turn, the normal reason anyone bolts a tablet to a dash.
  • The car's own dashboard - the tablet joins the OBD Pi's wifi access point and opens the Pi's HUD: live speed, RPM, estimated gear, coolant, fuel, trip data, fault codes. That HUD and the Pi behind it are their own writeup.

So the tablet never needs mobile data or the internet to do its main job. The Pi is the data source, the tablet is the glass, and both live on a little network inside the car.

Sharing power with the OBD Pi#

Three things now hang off the dash: the head unit, the tablet, and the OBD telemetry Pi that polls the car over Bluetooth and serves that HUD. They share one switched-power plan: an 8 AWG feed from the battery with a fuse near the post, a distribution block in the cabin, and an ignition/ACC signal through a relay so everything dies when the key turns off.

The head unit takes its switched-live the normal way, through the ACC pin on the ISO power plug. The Pi bus takes the same ACC signal to trigger a clean shutdown before the relay cuts 12V, so the Pi never loses power mid-write, and the tablet charges off that bus. One ignition signal, three consumers, nothing draining the battery while parked.

The order that matters#

Do the connector identification before you order anything for the radio. Everything else on the audio list is standard 1-DIN hardware that fits any car; the only Clio-specific decisions are the fascia, the antenna adapter, and which radio harness you need, and that last one is the only place the audio side goes wrong.

The tablet is the opposite kind of job. The hardware is trivial - any tablet that physically fits the slot. The work is all software: root it, strip Google, put microG in its place, and lock it into kiosk behaviour so it is a dashboard and not a distraction.