The UK quattro Network
Audi ur-quattro ISO Radio Connections
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© The UK quattro Network 2004-2006. All rights reserved
The radio is one of the worst documented features of the Audi ur-quattro.
Perhaps this is because of Ferdinand Piech's dictum that a sports car is best
defined as "a car in which it is pointless to fit a radio". Perhaps it also
reflects a consumer attitude gulf between Germany and the UK - Germans refuse
car manufacturers' attempts to "foist inferior radios on them at silly prices"
(and there has been consumer legislation on the subject in Germany) whereas
Britons object to "a high-priced car without a radio".
Despite the availability of the excellent Philips
MCC, UK ur-quattros were fitted with markedly inferior Blaupunkt Toronto SQR
44s. All were connected using the DIN system - a four-pin plug for power, ground
and aerial control, with a separate pin-and-blade connector for each
loudspeaker. Fitting a modern top-line radio, CD changer or satellite navigation
system requires rewiring the radio connections to the newer ISO standard.
ISO Car Radio Connections
ISO car radio
connectors - back of radio or cable side of connectors
In the UK, excellent
connectors are available from Halfords. There may be up to four - connectors
A and B are mandatory and often formed as a single unit.
- Connector A is often not fully populated since some pins are used only by
satellite navigation systems. Audi part number 000 979 225A is a wire with the
correct pin crimped onto both ends - it just pushes in to the connector from
the rear.
- Pin 1 - GALA - Geschwindigkeitsabhängigelautstarkeregelung -
speed-dependent volume control. This pin is used in some radios to increase
the volume automatically at speed, and by satellite navigation systems. It
needs input from the speed sensor - more correctly known as the distance
sender. The signal can be taken from the electronic dashboard or cruise
control, if fitted. In the MB and RR ur-quattros, it can also be taken from
the rear differential lock controller or the idle stabilisation computer.
The wire is usually coloured red/yellow. When a cable speedometer is fitted
and the car does not have cruise control (many analogue dashboard cars) a
separate wheel sensor must be fitted - e.g., Bosch 7 607 611 093.
NOTE: If the speedometer stops working after the radio has been
fitted, this pin has most likely been grounded by the radio using the pin
for some function other than GALA. Detach this wire and see if the
speedometer returns to normal. On MB and RR-engines cars, this signal also
controls idle stabilisation and the automatic differential unlocking
system
- Pin 2 - mute control - grounded by external components to mute the
radio, often used when a mobile telephone is fitted to the car. See the
telephone handset installation instructions. On a 1985,
1986
or 1987
ur-quattro with a green digital dashboard, this pin should also be connected
to pin 16 of the voice synthesiser/autocheck unit so that the radio can be
muted when warning messages are issued.
- Pin 3 - RFLS - Ruckfahrtlichtschalter - the reversing light switch. Satellite navigation
systems use this signal, the GALA signal (pin 1 above) and an internal laser
gyroscope for "dead reckoning" in the absence of satellite signals. +12v
input to the radio with the ignition on and the car in reverse gear.
- Pin 4 - permanent +12v input to the radio from the battery, already in
the DIN radio harness.
- Pin 5 - automatic aerial - +12v output from the radio, maximum 150mA, to
drive an automatic or electronic aerial. From 1985 onwards this is a white
wire in the radio harness - different colours were used on earlier cars;
check the colour of the wire in the small single pole connector on the radio
aerial. If present it MUST be connected, even if the aerial is not
automatic. It also operates the buzzer that warns of the radio being on when
the door is opened - see the note below.
- Pin 6 - illumination - +12v input to the radio when the car's lights are
on. In some radios this actually lights the display - in others it dims it,
reverses the black-on-white aspect, or even changes the colour from green to
orange. If the dashboard has a dimmer function, this pin should be connected
to the dimmed part of the display. The wire to the cigarette lighter bulb -
usually grey/blue - can be used.
- Pin 7 - ignition - +12v input to the radio when the ignition is on. On
ur-quattros with the combined LED voltmeter and oil temperature gauge, the
black wire to pin 2 on that unit is a useful source of switched 12v. On
earlier cars, the power feed to the differential lock lights should be used.
- Pin 8 - chassis ground - already in the DIN radio harness, but usually
black instead of Audi's normal brown.
Note that VW and Audi normally
installed radios in such a way that they operated with the ignition off -
thus one wire in the standard DIN connector is a permanent +12v equivalent
to pin 4 above. This is because of ecological concerns raised when the
German forests started dying off in the late 1970s - people waiting in cars
for friends to come out of their houses would idle the engine just to listen
to the radio. Connecting the radio directly to the battery (usually via Fuse
4) eliminated the requirement for the ignition to be on. Some more modern
radios have automatic power-off functions.
- Connector B is for the loudspeakers. Which loudspeaker a particular pair
of wires goes to can be identified using a small battery - preferably a
mercury "button" cell or a discarded AA or AAA battery with very little charge
left in it. The loudspeaker will click noticably. They only have a resistance
of around 4 ohms, so 9v batteries must not be used. The wires are in obvious
pairs - the one with the stripe is the "+" sense.
- Pin 1 - Right rear speaker +
- Pin 2 - Right rear speaker -
- Pin 3 - Right front speaker +
- Pin 4 - Right front speaker -
- Pin 5 - Left front speaker +
- Pin 6 - Left front speaker -
- Pin 7 - Left rear speaker +
- Pin 8 - Left rear speaker -
On green digital dashboard
ur-quattros, some of these wires must be passed through the voice
synthesiser unit. If a separate amplifier is fitted, note that the voice
synthesiser outputs at high volume. The test function (depress the computer
reset button while switching on the ignition) can be used to adjust the
amplifier's gain control. It may prove better to attach the mute (pin A2)
and provide a separate small loudspeaker for the voice synthesiser output.
- Connector C may not be present at all - sometimes, only parts of it are
present. It usually comes attached to the device it supports:
C1 - external amplifier or equaliser
- Pin 1 - Line out left rear
- Pin 2 - Line out right rear
- Pin 3 - Line out ground
- Pin 4
- Pin 5
- Pin 6 - +12v switched - maximum 150mA
C2 - remote control
- Pin 7
- Pin 8
- Pin 9
- Pin 10 - +12v switched - maximum 150mA
- Pin 11 - Remote control in
- Pin 12 - Remote control ground
C3 - CD changer
- Pin 13 - CDC data in
- Pin 14 - CDC data out
- Pin 15 - +12v permanent
- Pin 16 - +12v switched - maximum 300mA
- Pin 17 - CDC data ground
- Pin 18 - CDC audio frequency ground
- Pin 19 - CDC audio frequency left
- Pin 20 - CDC audio frequency right
- Connector D is only present on satellite navigation systems - it is
documented in the relevant manuals.
Halfords' adapter range is indeed excellent - each wire
has its function printed on it as a useful confirmation that connection is
correct. There are DIN to ISO adapters and ISO to DIN - if fitting a modern
radio into an ur-quattro, the best strategy is to adapt the existing harness
entirely to ISO and purchase the ISO to DIN adapters in case anyone wishes to
replace the original radio. Leaving a short piece of wire attached to each
loudspeaker plug will allow the plug to be crimped onto the leads of an ISO
adapter so that a radio with DIN loudspeaker connections can be
fitted.
Note that the original Blaupunkt SQR is now a collector's item -
eithe retain it with the car for a future owner or sell it via eBay.
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