Audio Systems: pontiac monsoon cd player, car fuse, marker pen

Question
I bought on ebay monsoon cd player. I installed the head unit and worked for 15 minutes when I hit a bump in the road and the unit went dead. The car fuse is good. Can you help?

Answer
Hi There

There is no magic answer that will sort this out I afraid, you will have to dig in and check it out wire for wire.
I attach below a copy of the idiots guide to radio installation, it might help you establish the basics and eliminate the problem with a bit of luck. You might like to skip straight to the power section as I don't think it's a speaker problem, more like a dropped connection.

Basic test and diagnostic procedure for car wiring harness.You will need the following;

A test meter set at 20vdc or a test lamp (two wires on a 12v bulb) or probe (like a screwdriver with a 12v bulb in it and a lead and clip)
Some masking or paper tape to label wires and a marker pen,
An “AA” or “AAA” torch battery, (or borrow one out of the TV remote for an hour)

First the easy stuff, the speakers, (without amp!)

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. 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.

Power leads connector.
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’.
Switch off ignition and switch on the side / park lights, repeat test until you find a third live, label this ‘lights’. Switch off the lights.
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. Clip tester to +30 and probe one of the remaining wires, if you have an electric ariel it will go up. Connect your DIN plug to the correct wires and jobs a good un’.

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)
Hope that helps, Peter