Pinouts >  Aftermarket automotive Head units and Car Stereo
36 (20+8+8) pin Head Unit / Car Stereo ISO connector layout
36 (20+8+8) pin Head Unit / Car Stereo ISO connector
ISO 10487 is a standard connector that is used in the radio unit (head unit). There are contacts for the power supply off / on (controlled by the ignition key), the speakers and automatic antenna.

Car audio ISO connector A pinout

Wire color* Description
1 A1   SCV - speed-dependent volume control. This pin is used in some radio equipment to automatically boost up the volume. It needs the output from the speed sensor. Note: If the speedometer stops working when the radio is connected, then the pin is probably grounded because radio probably uses this pin for another function, except for GALA. On some equipment this pin is used, instead, for the rear-view camera control input, which carries the 12v backup-light signal to the head unit to tell it to display video from the backup camera.
2 A2   Mute from Cell-Phone. This pin is used to silence the audio cd, earthed by some other external components such as a mobile phone that is connected to the radio.
3 A3   the reversing light switch. Satellite navigation uses this signal, the GALA signal (pin 1) and an internal laser gyroscope to calculate position in the absence of satellite signals. +12 V input on the radio with the ignition switched on the ignition and the car is in gear to move backwards.
4 A4 YELLOW Memory Power (12V direct from Battery). Connects the radio directly to the battery.
5 A5 BLUE Power for Electric Antenna. Output from the stereo +12 V (maximum 150 - 300mA) power supply for automatic or electronic antennas.
6 A6 ORANGE/WHITE Dial-light illumination (car side light circuit). +12 V input on the car when the lights are on. For some it actually illuminates the radio display - the others can dim the lights. If the dashboard of your car has a light control function, this pin should be connected in order to regulate the brightness. The wire from lighting a cigarette lighter can be used for the same purposes.
7 A7 RED +12V Main Power (Switched via Ignition key). +12 V with the ignition key is in the ACC or ON position.
8 A8 BLACK Ground (Chassis)

*Wire colors are typical and may be changed without notice.

a4 and a7 pins may be reversed (a4=acc switched,  a7=batt fix) in some Head Units, i.e. sony japan . A7 and A4 must be connected to +12V to get radio power on.


Car audio ISO connector B pinout

Connector B is used only for the speakers. Which wire goes to which speaker can be easily determined with a battery of 1.5 V. Speaker will click and you will see the diaphragm move forward or backward. Speakers must be properly phased (note the + and - half on the speaker), because otherwise you will have weak bass. Wire with a stripe usually goes to + pole of speaker.

Wire Color
1 B1 PURPLE Right Rear speaker+
2 B2 PURPLE/BLACK Right Rear speaker-
3 B3 GRAY Right Front speaker+
4 B4 GRAY/BLACK Right Front speaker-
5 B5 WHITE Left Front speaker+
6 B6 WHITE/BLACK Left Front speaker-
7 B7 GREEN Left Rear speaker+
8 B8 GREEN/BLACK Left Rear speaker-

Car audio ISO connector C pinout

Connector C are consist of 3 separate connectors that are tied together. It is not always present, sometimes only a part.

1 C1 Line out left rear
2 C2 Line out right rear
3 C3 Line out ground
4 C4 Line out front left
5 C5 Line out front right
6 C6 +12v switched - maximum 150mA
7 C7 RXD
8 C8 TXD
9 C9 Chassis ground
10 C10 +12v switched - maximum 150mA
11 C11 Remote control in
12 C12 Remote control ground
13 C13 CDC data in (bus)
14 C14 CDC data out
15 C15 CDC +12v permanent
16 C16 CDC +12v switched - maximum 300mA (+A)
17 C17 CDC data ground (+U)
18 C18 CDC audio frequency ground
19 C19 CDC audio frequency left
20 C20 CDC audio frequency right

Warning! The connector wiring may vary depending on the car manufacturer!

Take special care when installing into ’98 or later VW/Audi/Skoda/Seat models as there may be a 12 V connection on Pin A5, which could damage the car stereo or into Ford from ’97 or later, with an ISO connector, on which damage to the car’s microcomputers is possible if misconnected.

According to 26 reports in our database (22 positive and 0 negative) the Car Audio ISO connector pinout should be correct.

Is this pinout
Car Audio ISO connector visual pinout:click to enlarge
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