Expert: Peter G. Lee - 8/5/2006

Question
1985 Jeep Wagoneer I Have been looking for a diagram on the radio wiring system in my car and I can't seem to find what wires go to what. Can you please help me?

Answer
THE FOLLOWING IS THE PROCEDURE I FOLLOW IN A CAR I DON'T KNOW,

You will need;
An AA torch battery
Some paper / masking tape for labels
A pen
Paper to make notes
A 12v test probe, (like a screwdriver with a lead and clip on it and a bulb inside)
(Or a test meter set to 20VDC)

Favourite beverage x 4.

Speaker wires. These are normally twisted together in pairs if you are lucky and are the same colour for each pair but one with a colour trace on, i.e. blue and blue/white, green and green/white. (but not always) Touch a pair across the battery and you will hear a noise on the corresponding speaker, label it (e.g. left rear), continue until all four are identified and labelled.

Drink

Earth one side of your meter or tester to a metal part of the car, probe each wire until you have a wire that is live all the time with the ignition OFF, label this ‘+30’.
Switch on ignition and redo test until you find another previously dead wire now live, this is ‘+15’ accessory.
Switch off ignition and switch on the side / park lights, repeat test until you find a third live ( NOTE, if fitted, not always there), label this ‘dimmer’. Switch off the lights

Drink

You should now have two or three left. One will be earth, (usually black or brown); one could be to an amp and or electric ariel (usually blue or blue/white) and one for phone mute if fitted, (sometimes white but it would go to a phone holder or hands free unit). Connect your DIN plug to the correct wires, test and jobs a good un’.

Two drinks!

DIN connections are.

Speakers

Right rear -,  right front -,   left front -,  left rear-,
Right rear +, Right front +, left front +, left rear +

Power block viewed from cable side

Phone mute (white),/   n/c, /      ariel & amp (blue), /ignition (red)

N/c, / 12vlive, (yellow or orange), / lights, (various colours),/ negative (black)