On Tue, 08 Aug 2006 17:59:07 GMT, ITM
wrote:

The fact that the supplier found no fault with it indicates that the
problem is with the connections in this vehicle, but the fact that the
other head unit works fine eliminates alot of the potential causes.

The fact the OEM unit works should be completely ignored - all that
this tells you is that there is power somewhere on the car connector
as a lot of OEM units will work quite happily off a single supply
feed.

If the unit works out of the vehicle, then there are only really 3
possible causes - no ground, no permanent live or no ignition live.

Disconnect the wiring harness from the back of the radio, then measure
the red and yellow cables with a voltmeter. Both should have +12v
present with the ignition on. If either is missing, it's almost
certainly a blown fuse in the car.

Measure from the black wire to chassis ground with an ohmmeter. This
should read less than 1 ohm. If it doesn't, you'll need to run a new
ground lead to chassis ground.

With all of the above, the radio must be disconnected at the time,
otherwise you'll get false readings caused by the internal resistance
of the unit, or from voltage going to ground from the unit.

Jon
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